Exploring the world of vision

Interview with Susan Barry

2011-06-15T01:57:00.000-07:00

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Interview with Susan Barry by Eduardo Punset on TV program "REDES" talking about Optometric vision therapy.

The Mystery of 3D - Why somepeople see it and others not.

2010-02-16T06:33:00.000-08:00

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“Avatar”, as other recent movies, has led the wish to watch movies in a diferent format we are used to or we watch everyday on our televisions.

I suggest to you read this article. Surely you will solve many questions about why some people watch 3D movies without any problem and others feel uncomfortable or can not watch them.

This visual problem can be solve easily with vision therapy in many cases (except in strabismus, amblyopia, monovision or monocular vision).

OTHER LINKS

Don't be startled if 'Avatar' makes you nauseated

Avatar 3-D Images Help to Identify Vision Problems

Physiological defect: Presbyopia.(3) Solutions

2010-01-21T05:57:00.000-08:00

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Solutions

In the case of myopic people with fewer than -3.00 diopter, compensate presbiopia for a long time simply by removing their eyeglasses in order to read. I remind you that the myopic people focus the image in front of the retina, and that the presbyopic people focus the image behind it. Here I explain it better:

A young myopic that looks far away through her well corrected eyeglasses, focuses the image on the retina; when she has to look something at close with her glasses, the image goes behind the retina, but her accommodation helps her to focus it on the retina again.
Thus, in the case of presbiopic myopic without eyeglasses, when she looks far away, she sees blurry because the image is focused in front of the retina; but when she looks something at close, the image goes back, bringing it closer to the retina, and consequently, seeing it more clear.

The most common method to compensate the presbyopia is through some OPHTALMIC LENSES in eyeglasses; but depending on the use of the eyeglasses, that is, for what activities or distances you will use them, there are different options. Therefore, whenever you receive a visual examination, you must give the optician some information about your needs in near vision (reading, computer, work distance, etc.), so that, she can recommend you the best option in your case.

Basically the compensation of presbyopia requires the use of convergence or positive lenses (magnifying glasses) for near vision tasks. From here, we play with different variations.

Progressive lenses: These are the lenses that are most used, although their adaptation is not easy.

These lenses allow to have clear vision at all distances (from far away to up close) simply by changing the inclination of the eyes or the head; this is something everyone wishes, specifically if the focus distance has to be constantly changed. But these lenses have got two main inconvenients:
1. they have a vertical “corridor” of central vision that is more narrow than any other lens (due to optic aberrations in both side of the lens); therefore, when we look out of the corridor, the vision is blurred;
2. and we have to learn to use these lenses, since we have to learn by which areas of the lens we must look at, depending on the distance where we want to see. Once achieved, the effort will be worthwhile.
Bifocals lenses: These are less used lenses (before the progressive lenses appeared in the market, these were the best option), but for those people with certain binocular problems, whose daily activities require clear distance-near vision, and when they do not accept the progressive lenses, the bifocal ones may be their only option.

The top of the lens has a graduation which is required to see clear distance objects; and the bottom part has a “segment” that has the addition required to see clear close up objects AT A CERTAIN DISTANCE.

Advantage: The adaptation is much easier than the progressive ones, because the bifocal lenses do not have so many aberrations, nor so many areas with different graduation for different near distances; simply by performing two eye movements, we can focus far away or close.

Disadventages: Precisely the last advantage is a disadvantage as well: the bifocal lenses allow clear vision in only two specific distances (they lose the intermediate distance) and they are less aesthetic, “they betray the age”.

Trifocal lenses: They are lenses basically obsolete.

Reading lenses: These are the best option for those that see very well far away, so they need nothing for distance. They are lenses with only one graduation, so, they are prefect in order to perform prolonged near tasks.

In this option there is not any specific size of eyeglasses. But if you need to alternate your vision in different distances, mainly far away-close up, it is more recommended to use narrow glasses, known as “half moon reading glasses” which let you look over them when you look far away, without performing strange head positions or movements.
These small glasses have one inconvenient: as the bifocals lenses, they also “betray the age”, although nowadays there are many models of eyeglasses which do not have the typical shape of “half moon”, and that can be perfectly fine.

Reading glasses work well with contact lenses.

Ready-made reading glasses: They are standard reading glasses, that is, they are the same for everyone. THIS IS NOT AN OPTION. These glasses are only good for pulling through at a specific given time, nothing else. But I will write about these glasses in other post.

PROGRESSIVE CONTACT LENSES: The adaptation is even more complicated than with progressive lenses in eyeglasses, but the success rate is increasing. The complication resides in that the brain is responsible for learning what RING of the contacts has to look for, depending on whether it wants to focus far o close. It is not easy for everybody, and not everyone achieves a successful behavior.

With this kind of contacts, a type of adaptation is usually performed called MONOVISION: one eye has better vision for looking far away and the other eye has better vision for looking at near.

Besides these solutions, I have mentioned above, during last years the cataract surgeries have promoted the research of the INTRAOCULAR LENSES with accommodative capacity: the ophthalmologist removes the crystalline lens and puts a new lens inside of the eye, with the suitable graduation.
More information

MERRY CHRISTMAS AND HAPPY NEW YEAR

2009-12-25T02:18:00.000-08:00

To my dear readers...

Physiological defect: Presbyopia.(2) Causes and risk factors

2009-10-20T08:08:00.000-07:00

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Causes

As I explain in a previous post, presbyopia is a visual disorder that is product of the time as it goes by.
When we look something at near something in order to focus and to see clear, a phenomenon is caused in our eyes called ACCOMMODATION, and the lens has to change its shape so that the image of what we see, is focused on the retina. But over the years, on one hand, the ciliary muscle, as the rest of body muscles, gets more rigid and shorter; and on the other hand, the lens increases the thickness of its faces, thus losing its elasticity (this therory is the most approved one). So, the muscle loses the ability to contract itself to allow that the lens to be more convex (at the same time, the crystalline lens does not do it because of its stiffness), and the accommodation does not happen.

This loss of accommodation process is gradual. It begins affecting the vision in the closest distance, and the changes of focus in different near distances are slower and with worse quality (those changes of focus are what we call “accommodative flexibility”). Little by little the ability to focus on near distances and increasingly farther from oneself its more difficult; this happens when our arms begin to stretch and in a certain moment they seem short. When it happens, this indicates that our focus is failing and we need a lens that compensates the accommodative effort that we can not perform anymore.

When a child is 10 years old, has an accommodation of around 14 diopters (that means, the closest distance where she can focus something very small is at around 7 cm); this quantity decreases linearly with the age, until that, at 50 years old, the accommodation is around 2.50 diopters (the closest distance where she can focus something very small is at around 40 cm, as you see the focusing ability has decreased almost 6 times the one of the child).
This process begins between the 40’s and 50’s (depending on the refractive error that we already have at a young age; at the beginning the presbyopia starts adding a little positive lens for near distance -1.00 diopter approximately - over the graduation that we need to see far away); it usually stops around 58 years old (with a addition of around 2.25 or 2.50 diopters).

Presbyopia equally affects everyone, but hyperopic people start to suffer it at an earlier age than the emmetropic one; and these ones earlier than myopic people. Some of these myopic people (low and medium), when the presbyopia appears in their lifes, they are capable to read without using their eyeglasses, because of the compensation that is caused between both phenomenons.
From the moment presbyopia appears, this increases during a period of 10 or 12 years and then it is strabilized. Some of you, seeing how fast presbyopia increases when it begins, might think that it will never stop, but I assure you that it does.

In the case of some emmetropic or low hyperopic people, they suffer an increase of hyperopia after using reading eyeglasses of +1.00 dipoter during some time, when presbyopia is evident; so that after a couple of years, that graduation is not enough for the close up tasks, but they are only useful for distance vision. This is called HYPEROPIA OF PRESBYOPIA.

Risk Factors

According to American Optometric Association

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Physiological defect: Presbyopia.(1) Vision, Appearance and Symptoms

2009-10-20T05:49:00.000-07:00

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Presbyopia is what everybody knows as “old sight”. It is not considered as refractive disorder or an ocular illness.

Vision of presbyopic

The typical complaint in presbyopia is “BLURRED VISION AT CLOSE DISTANCE”. A presbyopic person stretches her arms in order to see better, but in a certain moment “THEY ARE TOO SHORT”.

Distance vision may have not any changes, at least in the first stages.

Appearance of presbyopic eye

The shape of the eye is like a myopic or hyperopic or even emmetropic one at young age; but the difference is given by the crystalline lens. When a person looks at objects up close, she is not capable of focusing them on the retina, but behind (as hyperopic people), therefore seeing them blurred.

Prevalence

Everybody will have suffered presbyopia sooner or later, after 45 years old.

As presbyopia is age-related, its prevalence is higher in societies in which larger proportions of the population survive into old age.

For instance, from all Spanish population, 43% suffers “old sight”. And from this 43%, 7% of presbyopic people have never checked their vision in any previous occasion. Because of the increased life expectancy, within 10 years, more than half of the Spanish population will suffer from this condition.

It does not exist any way tested to be true in order to prevent it.

Symptoms

Incipient presbyopia (the first symptoms)

It is difficult to maintain the performance of near task in a continuous way.
Headache because of the continuing effort.
The letters seem to move on the paper.
More light is necessary in order to see better.Near vision is worse at the end of the day.
Sometimes it seems that we “do not control” our eyes (as the accommodation and convergence are related, the gradual loss of accommodation involves the progressive worsening of our fusion, resulting in Convergence insufficiency, and even in a double vision when we are more tired).

Evident presbyopia

We stretch our arms in order to find the distance where we can read whatever we want, until a certain moment where we do not get to read although we stretch them completely.
At the beginning presbyopia only affects near distance (documents, handicrafts,…), and little by little it starts affecting intermediate distance too (computer,…)
We tend to avoid the small texts and precision tasks in near vision whenever we can (we do not sew anymore, we do not read so much, we do not perform certain leisure activities that we liked… :-( )
We always look for natural light or a good light lamp.
It is usually accompanied by “Dry eye”.

World Sight Day 2009 (WSD)

2009-09-17T01:48:00.000-07:00

Información en español

8 OCTOBER 2009

World Sight Day (WSD) is an international day of awareness, held annually on the second Thursday of October to focus attention on the global issue of avoidable blindness and visual impairment. This year, it focuses on gender and eye health–equal access to care.

VISION 2020 is the global initiative for the elimination of avoidable blindness, a joint programme of the World Health Organization (WHO) and the International Agency for the Prevention of Blindness (IAPB) with an international membership of NGOs, professional associations, eye care institutions and corporations.

Over the next two decades, Vision 2020 will take steps to prevent an estimated 100 million people from becoming blind.
Vision 2020 focuses on creating adequate eyecare facilities, a foundation of well-trained eyecare
workers, implementing programmes to control the major causes of blindness, and integrating
eye-care into general health care services... (more)

More information:
VISION 2020: The Right to Sight
What is VISION 2020: The Right to Sight?
International Key Messages

Refractive disorders: Astigmatism.(5) Solutions

2009-08-31T04:31:00.000-07:00

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Solutions

Just as myopia and hyperopia, astigmatism can be corrected with eyeglasses, contact lenses and/or refractive surgery.
In any treatment, the correction is more complex because of the asymmetry of this refractive error.

Eyeglasses, with usually the same correction to look far away and to look up close (although there are some cases in which the astigmatism may be different in one distance or another).

The lenses used for compensating astigmatism depend on the kind of astigmatism we have.
So far, the compensation of a refractive error was simple, because a spherical lens modified equally every ray that crossed it at any point of it; that is, any ray that got to the lens, got to the retina. In the astigmatism, this is MORE COMPLICATED.
Because all surface (of cornea or crystalline lens) has not got a symmetrical curvature (there will be a meridian with more curvature and other with a lesser one), the light that gets into the eye, gets to different points regarding the retina. Therefore, if we put a spherical lens in front of a astigmatic eye, it will only correct a meridian. This way, all rays, that go through the lens and later through the eye, will keep on getting to different points with respect to the retina, because some of rays will be focused on it, but others will be focused behind or in front of the retina (depending on the kid of astigmatism).

To make it simpler. Think that an astigmatic person sees the image distorted; on the other hand, it is usually accompanied by hyperopia or myopia that causes seeing blurred images. So, for you to understand it better, “this person will see blurred through one meridian, and distorted through the other”. Consequently, we need a lens with two different powers to compensate both effects: one spherical lens to compensate the blur and other cylindrical or toric lens to compensate the distortion. Each one will focus the rays that go through by each meridian, INTO the retina.

The eyeglasses with astigmatism may usually make you feel a little sick when you begin to use them, mainly with refractions over 1.00 or 1.50, that is why it is advisable to start using them gradually. In fact, in high degree, firstly diagnosed astigmatism, the graduation is usually prescribed gradually, increasing it little by little.

In the past, astigmatism could only be compensated with eyeglasses, because the cylindrical lens demands it to be worn with specific angle degrees. The contact lenses on the eye ares in constant movement because of the blinking, and in the past, this prevented that stability from happening. When said contact lenses were made, these were made with a material that lasted for a long time, because manufacturing was expensive. Latter research lead to the current situation, where there are many systems to stabilize them, and the cylindrical power in disposable contact lenses is higher and higher as time goes by.
Therefore, nowadays, this refractive disorder may be compensated with soft contact lenses as well as with lenses; and in adults as well as in children.

In the cases of astigmatism caused in keratoconus, they are usually compensated with rigid gas permeable contact lenses, with the purpose of holding the process of growth of the cornea a little bit. But sometimes we choose the soft contact lenses in the cases where the other lenses are impossible to wear due to the blinking; on one hand, because the eyelids may expel the lenses; and on the other, because they are not stabilized in the best position possible, therefore causing blurred image. Anyway, these patients usually achieve better Visual Acuities with contact lenses than with eyeglasses.

Also, the astigmatism caused by a problem such as a deformation of the eyeball by palpebral disorders (as chalazion), treating the underlying cause will resolve the astigmatism. If the patient suffers a severe astigmatism, her best option is the semi-rigid permeable contact lens.

In the other hand, vision therapy is useful when the visual system has been compensating a little difference of graduation from between some meridians and others, and the focusing (accommodation) and team coordination (fusion) are tired.

We use vision therapy when symptoms exist and we have to teach the visual system to use its accommodation correctly again.
Many times simply wearing some eyeglasses is just not enough because they do not resolve completely the problem.
Although initially you see well with them or maybe you have started to use them and everything seems to be going better, shortly you may be uncomfortable again and unable to perform at work or when studying.
During a time you were using your visual system incorrectly and you have to re-educate it; the eyeglasses by themselves will not do it.

As the previous refractive disorders, the VISUAL HYGIENE AND ERGONOMIC RULES must always be taken into account.

And finally, the refractive surgery is another option. It consist of changing the shape of the cornea, and therefore correcting the astigmatism in the cornea or in the crystalline lens.

Refractive disorders: Astigmatism. (4) Symptoms.

2009-08-10T02:12:00.001-07:00

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Behavior of astigmatic people

A low degree of astigmatism USUALLY causes more symptomatology, because the visual system tries to compensate it, and does not show blurred vision symptoms; therefore, at the beginning people do not usually associate the symptoms to a vision problem.

The main symptom is the distorted and blurred vision in high astigmatism; and headache, visual strain, ocular itching and red eyes in low astigmatism.

As I explained in a previous post, a young hyperopic person with the low degree is able to “disguise” her disorder if her accommodative function works correctly. But in the case of an astigmatic person, although her accommodation is in correct condition, it “gets crazy”, because it has several points or images that fall in different planes regarding the retina; accommodation is constantly trying to focus all of them, without distinction. The closest points of the retina will cause less tension, but those that are farther will be more difficult to compensate. Visual system will be exhausted and the symptoms (red eyes, itching, burning, tearing, headache, visual strain,…) will appear.

Although a person with astigmatism is usually born with it, if this is low, she could compensate it during the infancy. But as the child grows up and the school request is higher (more number of homework or study hours, more reading, more understanding,…), and her accommodation naturally decreases, the child has got more problems to compensate it; and this moment is when the astigmatism is obvious, showing several symptoms. That is why, many people say their astigmatism appeared between 10 and 20 years old.

So, an astigmatism will cause more symptoms if it is associated with a hyperopia than with myopia, because hyperopic people have a more exhausted accommodative system due to the excessive effort that she makes to compensate her refractive error.

That is why astigmatism can also cause learning disabilities.

It can develop wrong postural habits, like tilting her head when looking far away or looking up close, since when the astigmatic person tilts her head, can find the position in which she sees better, or where the image is less distorted. This can cause cervical problems in the long run.

“Blurred” or double vision greater at near than at distance.

While she reads, she jumps the line or the letters seem to be moving.

Visual strain and feeling sleepy.

Headache mainly in the fronthead and in the eyes.

Photophobia (light sensitivity).

Frequent conjunctivitis or blepharitis.

Ocular injuries after solar exposure

2009-07-24T04:21:00.000-07:00

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A digression on the “Astigmatism series”.

Summer is here and many of you had already been on holiday or you are thinking about that, preparing everything to enjoy a well-deserved time for rest :-)

Do not forget to put in the suitcase sunglasses for all your family members (adults and children). Just as you do not forget the sun protection lotions, sunglasses are something indispensable to enjoy some safe holiday.

Think about the time that you are going to be performing outdoor activities, without your eyes being protected. Furthermore, there are more harmful radiations in the beach, because we have to add the ones that are reflected in the sea; but many surfaces reflect those harmful rays (sand, buildings, sidewalks,…). Even in cloudy days, with high clouds, the solar radiation that crosses them is nearly the same one that when there are no clouds at all. Only rain, fog and low clouds reduce UV radiation in a significant way.

Any tissue of the eye, as it happens with the skin, can be burnt. Solar UVA or UVB radiations on the tissues cause a cellular death process and a transformation of cell DNA, which can create irreversible disorders. Therefore, we must take care of our eyes by wearing lenses that comply with health regulations of visual quality. In the case of European sunglasses, the CE mark identifies glasses fulfilling quality regulations.

Atmospheric ozone is a barrier against very detrimental UVC radiation and other UV types; and this moderates the quantity of UVB that arrives to the earth (more harmful than UVA).
The constant slimming of ozone layer causes an increase of the UVB radiation that we receive daily. So, while this keeps being like that (unfortunately), we will have to do everything in our power to protect our eyes.

Some injuries that are caused in the eye due to solar radiation are the following ones:

IN CONJUNCTIVA (5)

IN CORNEA (1)
Cornea and crystalline lens absorb most of UVA and UVB radiation that get into the eye, damaging these structures; therefore, if a person has got a keratoconus or she has undergone a refractive surgery, her cornea will be thinner and it will be able to absorb less radiation, so, this radiation might get into the eye, causing some injuries.

Painful superficial keratitis
Photokeratitis or snow blindness
Climatic droplet keratopathy or Spheroidal Degeneration

IN AQUEOUS HUMOR (4)
The aqueous humor of the anterior chamber has a lot of Vitamin C (ascorbic acid), which is responsible for filtering UV radiation, and this way, achieving that the least amount possible of radiation gets to the crystalline lens.

A prolonged exposure to sunlight decreases the quantity of vitamin C in the aqueous humor.

IN CRYSTALLINE LENS (8)
The same as solar exposure can cause that your skin aged sooner, the same happens with the lens; it might suffer from a premature aging, because of the damages in DNA.

Cataratas

IN RETINA (10)
Looking directly at sun (in a eclipse or not), without adequate eye protection, causes a photochemical damage of the photoreceptors, inducing a burn at macular level (area of maximum vision of the retina) and being the reason of an irreversible blindness.

Early development of Macular degeneration
Melanomas

Refractive disorders: Astigmatism. (3) Different features

2009-07-21T03:12:00.000-07:00

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Development

Astigmatism relatively changes a little throughout all life.

Astigmatism is not very frequent during school age and it has got few changes of frequency and degree. One study made in Orinda, California, showed that the frequency of increase in an astigmatism of 1 diopter or more, at 6 years old, rises gradually from 2% by 3%, at 14 years old.

Higher levels of astigmatism are associated with moderate to high hyperopia during infancy, but both tend to decrease by the age of 5 years.

If a child is going to have a high astigmatism, it should already exist before beginning school stage.

In adult age, astigmatism does not usually change; if it do it, it usually indicates tension-related one, as myopia (in both cases vision therapy is very useful in order to structure a correct vision).

The little astigmatism that appears during infancy can be due to the strength that the upper eyelid exerts on the cornea causing that the vertical meridian to be more curve than the horizontal one.
In a more mature age, this astigmatism may change its shape, turning the vertical axis flatter, because of the laxity of palpebral muscle that rests on the eyeball. That is the reason why the axis or degrees of our astigmatism change through the years.

Prevalence

According to an American study published in Archives of Ophthalmology, nearly 30% of children between the ages of 5 and 17 have astigmatism.
On the other hand, a recent Brazilian study found that 34% of the students in one city of the country were astigmatic.
The National Autonomous University of Mexico revealed that astigmatism is the visual problem with most prevalence among people younger than 23 years old, and even 23% of population younger than 14 years old, put up with it.
Regarding the prevalence in adults, a study in Bangladesh found that nearly 32.4% of those over the age of 30 had astigmatism.
Also, several studies have found that the prevalence of astigmatism increases with age.

Factors and Causes

FACTORS:
If a child is going to have a high astigmatism or hyperopia, these will appear from birth or in early age. This means the factors are hereditary.

CAUSES:

High weight of the upper eyelid.
Slightly fallen upper eyelid (Ptosis).
Ocular contusions.
Corneal scars or lacerations, due to hits, injuries and infections in the eye.
Changes in corneal shape following eye surgery (refractive one, of catarata,…)
KERATOCONUS (this disorder will have its own post later, but let me briefly explain that the cornea acquires a conical shape as time goes by, and each time it gets thinner).
Metabolic changes, as for instance high sugar levels in the blood that changes the shape of the lens of the eye, and this causes astigmatism. When this sugar level is normalized, the lens usually gets back to its shape and said astigmatism disappears.

Refractive disorders: Astigmatism.(2) Appearance

2009-07-06T03:30:00.001-07:00

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Appearance of astigmatic eye

As I wrote in a previous post, one characteristic of the astigmatic eye is that the external face of its cornea -1- is not spherical (as a pure myopic or hyperopic eye), but elliptical. It is similar an American football cut in half (CORNEAL ASTIGMATISM).

But astigmatism may be more complicated than all that, since because the cornea has a thickness, the curvature of the internal face of the cornea may also cause an astigmatism that is more complicated to diagnose and treat; the same happens with the one that is caused also because of an unusual slope of the crystalline lens -8 (INTERNAL ASTIGMATISMS). Those last cases are less frequent.

But both of them (corneal and internal ones), may exist at the same time; and the addition of both, is the result of the total astigmatism that one person has got.

This typical shape of the ocular surfaces causes that their different "meridians" (horizontal and vertical ones) do not have the same power; therefore, some of them are more curve than others, and this causes the light is focused on two or more planes regarding the retina, instead of only on the retina itself. The light is clearly focused along one plane but is blurred along the other. The result is blurred vision at all distances.

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Refractive disorders: Astigmatism.(1) Vision

2009-06-30T03:45:00.000-07:00

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This third refractive disorder is the most common of them all, although the most known is myopia. This can coexist with myopia as well as hyperopia (13 percent of population has only got astigmatism, and 20 percent has astigmatism associated with myopia or hyperopia).

Astigmatic person’s vision

The typical complaints in astigmatism are “`BLURRED VISION´ MAINLY WHEN TRYING TO VIEW DISTANT OBJECTS, AND FREQUENT FRONT HEADACHE”. Only when the astigmatism is high, the complaint is also, “`BLURRED VISION´ AT CLOSE TASKS”.

If you realize I write 'BLURRED VISION' in quotation marks, because this refractive error, usually congenital, causes the outlines of the letters or the objects to be seen distorted; as if there would be some shadows behind every letter or every object, or as if they were seen double or distorted. Actually it is not a BLURRED VISION.

For low and medium quantities of refraction:

An uncorrected myopic person has low Visual Acuity at distance but it is good at near.

An uncorrected hyperopic person can have a good Visual Acuity at any distance as long as she has enough accommodation.

But, in spite of that a little astigmatism of about 0.50 diopter can not appreciably interfere in Visual Acuity in general, a person with uncorrected astigmatism does not have any distance where the image shaped in her retina is perfectly clear. In the case of a hyperopic astigmatism, by using help of the accommodation, it will be easier for itself to achieve better sharpness than a myopic astigmatism.

I am going to show you two simple ways for checking if you or your child has got astigmatism or not:

Put this image in the computer screen and get yourself away about 1 meter or 1 meter and a half, and covering one eye (and without wearing your glasses, if you have it), check if you can see ALL lines with the same contrast, that is, all of them have the same degree of “blackness” or all of them are clear or all of them are blurred.

If you do not have any astigmatism, the answer will be “yes”; you see it as it is in the drawing, or maybe all drawing is blurred (if you have some myopia or hyperopia).

But if you have it, the answer will be that you see something like this:

(Unless myopia or hyperopia, when we give the value of the astigmatism in a prescription, we give the power of the lens and also the axis of said lens).

This is the most common answer. It would belong to pure astigmatism between 180º and 150º (the astigmatic axis is perpendicular to the lines that you see better). If you have some myopia or hyperopia, as well the rest of axises will be seen out of focus.
Another clear way to check it is looking at the full moon. If you have some astigmatism, it will be impossible to perceive its outlines and it will be seen elongated and out of focus.

Refractive disorders: Hyperopia. (4) Solutions

2009-06-17T00:00:00.000-07:00

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Solutions

Low or even medium hyperopias are difficult to diagnose because, as I wrote in one previous post, they “consume” the refraction. Besides, they are difficult to be detected by parents or teachers because these hyperopic people have a more or less clear vision in any distance. That is why these people need a COMPREHENSIVE EYE EXAM from early age and a chekup once a year.
In that comprehensive visual examination the refraction that the visual system of the hyperopic person is constantly compensating is checked, along with other skills of the visual system, specifically her accommodation which is the one that is working all time, and if it (accommodation) may have disturbed other visual skills.

In the case that the refraction error can be diagnosed or that the error is causing a certain symptomatology, these are the possible solutions:

Eyeglasses, either if she needs them to see clear because she has a high hyperopia, or if she has a low one and needs them to avoid that constant effort for close-up tasks, and this way, avoiding certain symptomatology. In the last case, eyeglasses are not used for seeing clear.

In the case of a high hyperopia, the use of eyeglasses can make sense both for short and long distance seeing, if the visual acuity for long distance is reduced.

In the case of lower hyperopia, that is causing some symptoms, the option of eyeglasses is good because she does not require wearing them during all day.

Hyperopia is corrected with plus, positive or convex spherical lenses (thicker at the middle than in the edges of the lens), that optically falls in front the image, on the retina.

If hyperopia is higher than +1.50 diopter, another option for compensating it, is by wearing contact lenses for a long period of time. In this case, unlike myopia, each patient may use the best contact lens for her, that is, there is no suitable specific one. There is no one that stops the hyperopia, simply because as I have explained, the hyperopia does not increase.

There exists a research about Orthokeratology, carried out specifically in Australia, which tries to find a contact lens that model the cornea and reduce the hyperopia; but even, as I say, it is under research.

Hyperopic people are usually more uncomfortable wearing contact lenses than eyeglasses, because although her visual field is bigger wearing contacts, the size of images is more real; but wearing eyeglasses with plus lenses, they magnify the objects (I will explain this effect later); therefore, as they see everything bigger wearing the glasses, they are more comfortable wearing them than with contact lenses.
Vision Therapy is the best allied in this refraction disorder. A hyperopic person does not often respond to lens correction alone, but they are required to “remediate” accommodative dysfunction. With therapy we teach her to control her accommodation and her convergence and to perform her close-up tasks without effort. We will avoid that this to happen again.

Within vision therapy, besides some simple visual activities, the use of eyeglasses with a low positive refraction will be able to relieve her symptomatology in order to be able to perform the daily close-up tasks. This way, she relieves all accommodative effort that she constantly performs.
Besides, as it happens with myopic people, some simple VISUAL HYGIENE AND ERGONOMIC RULES will help prevent her reaching that visual stress. Modification of the patient's habits and visual environment is occasionally useful as an adjunct therapy.

Mainly:
- Improving lighting or glare reduction
- Using better quality printed material.
- Decreasing temporal demands, with frequent rests.
- Looking far away and focusing on something, frequently, when performing close-up tasks.
- Etc.

Lastly, surgery: hyperopia is a refractive defect that can be operated as well, but except for high hyperopias, it is not considered as the best option.

Refractive disorders: Hyperopia. (3) Symptoms

2009-06-01T10:38:00.000-07:00

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Hyperopia degrees

Low: 0 - (+2.00) D
Medium: (+2.25)-(+5.00) D
High: More than +5.00 D

Behavior of hypermetropic people (symptoms)
Usually, if hyperopia is low, hyperopic people do not have any symptom, and the time can go by until they show any. Besides, the younger the person is, the lesser the symptoms she will have, since her accommdation works perfectly and therefore, she can compensate the problem without any effort.

Either medium hyperopic, or not so young people or in certain cases will show (without wearing the refraction) the following symptoms:

Constant or intermittent blurred near vision.

If hyperopia is medium/high, it also affects distant vision.

Visual inconvenience when she performs close-up tasks.

Headache, visual strain, ocular pain, burning, itching, tearing, red eyes… (due to incapacity of keeping the effort of accommodation that is demanded).

In the case of low hyperopia that people have always been able to compensate without any problem (both as from a distance and as close up), as time goes by or in a special period with too many close-up tasks (at work or at school), they show inconvenience and discomfort and they do not know the reasons why they are caused. They have always seen well and have not had any previous visual problems; and they do not think, that this can be the cause of their problems. Before seeing blurred at near (while they can still keep the accommodation with effort), they usually show the symptoms above (headache, visual strain, itching, red eyes,...).

In the case of children or young people, they usually have problems with the reading: line jumping, jumping letters, letters “seem to dance”, “they don’t stop!”… (presbyopic or old sight people also say these same words). These symptoms cause that they have aversion to reading.

They as well perform facial contortions or frequent blinking while reading, that shows the effort that they are doing in their close-up tasks.

Poor eye-hand coordination.

In children (younger than 3 years old), if hyperopia is high, it can cause accommodative convergent strabismus (crossed-eye). This is because as they are young, they can perform much effort in order to see the image clear; but since accommodation and convergence are related (I will explain this better later), when the eyes perform too much accommodation, they also converge a lot, and one of eyes gets crossed. Consequently, this can also cause lazy eye or amblyopia on that eye.

In the case of low hyperopic people who have always been able to compensate without any problem and they have always had a enviable sight in their youth, they inevitably undergo presbyopia. But unfortunately for the hyperopic, they suffer it before that the rest of the people, before they are 40 years old. These people will think that their arms are shorter each time, because they need put their reading text farther (but this refractive disorder deserves its own post later).

Refractive disorders: Hyperopia.(2) Different features

2009-05-20T09:41:00.000-07:00

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Appearance of hypermetropic eye

The farsighted eye, unlike the myopic eye, is smaller than usual, or its lenses have less power.
Consequently, the image is focused BEHIND the retina.

Development

Some authors “…concluded that the growth of the eye during infancy is extremely rapid, and its adult size is reached by the age of 3 years…” and that “…the process of emmetropization is evident during the first year of life…”.

“…by the ages of 6 to 8 years old emmetropization has taken place, the great majority of the children being in the emmetropic group, which has its peaks at 1.00 diopter of hyperopia…”

There is a high percentage of children who were born hyperopic, because our eyes, when we were born, are not completely developed, and are small. As time goes by, if this hypermetropia is low, it disappears when the eye grows, so that sometimes, it can even turn it into myopia in school years.

Hyperopia, unlike myopia, do not usually vary until getting into adult years. At that moment, the appearance of presbyopia or “old sight” causes that the hyperopia increases much more, either hyperopia can appear or the myopia can even decrease.

Prevalence

Around 10% of people in Spain suffer from hypermetropia. 22.4% of population in USA and Australia is hyperopic. Specifically, there is a prevalence of 12.8% in American children aged 5-17 years.

In school years, hyperopia is usually lesser worrying than myopia because the clinically significant values of hypermetropia (and astigmatism) are 2-4% of the children who begin the school years, and also, these values do not increase over time.

“Hypermetropia is influenced by ethnicity. Native Americans, African Americans, and Pacific Islanders are among the groups with the highest reported prevalence of hyperopia. A study of 1.880 Chinese schoolchildren in Malaysia showed that the prevalence of hyperopia greater than +1.25 diopter, was only 1.2%”. (pag 8)

Probability

Factors

If you remember, environmental factors are very important in myopia; however, although the majority of children are hypermetropic when they start the school years, the hyperopia does not usually increase, but it decreases if anything.
Therefore, its existence is usually thought to be caused by hereditary factors.

In the other hand, a visual disorder derived from hyperopia is the presbyopia or “old sight”, that is typical of old people. In this case, this disorder is product of the time as it goes by. The ciliary muscle, as the rest of body muscles, loses elasticity and strength, and as well the capacity of being contracted; this way, the lens can not be more convex, and that prevents the accommodation to happen. That is why hyperopic people begin to suffer presbyopia earlier than emmetropic people; and these ones, earlier than myopic people.

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Refractive disorders: Hyperopia, Hypermetropia or Farsightedness. (1) Vision and Accommodation

2009-05-04T05:00:00.000-07:00

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Carrying on with the “refractive disorders series”, and seeing that there have not been a lot of questions or comments regarding myopia, I will keep on writing about hypermetropia or the “refractive defect of children and old people”.

Vision of Hypermetropic people

The typical complaint in hypermetropia is “INSTABILITY OF VISION WITH PROBLEMS AT CLOSE DISTANCE”.

Her distance vision is usually VERY GOOD; as many people say, a hypermetropic person has “EAGLE VISION”; but unlike myopic people, her visual system is an exhausted system, due to it is constantly trying to compensate her refractive error in order not to have any problems, both as from a distance and as close up.

Therefore, as the near effort is higher, the exhaustion will appear earlier at this distance; and therefore, blurred vision will appear first at near, and then, when the visual system is already very exhausted, she will also notice that she has poor distance vision.
But, what does this mean?
In order for you to understand it better, I need to briefly explain to you the concept of “accommodation”, which I have named it many times previously.

Accommodation

In the case of a person without refraction:

When she looks an object far away, the visual system must be totally relaxed so the image is focused on her retina and she sees in a clear way;

On the other hand, if she wants to see an object (a text, a watch, anything else) which is around 40 cm far from her eyes (for instance), her visual system has to perform the action of ACCOMMODATION, that is, the ciliary muscle has to be contracted and the fibers of the Zonule of Zinn have to be relaxed (to be stretched); this way, it allows that the lens -8- to be more convex, increasing its curvature, and also allowing its power to increase and letting the image of the near object that is being watched, to be focused on the retina, so it is seen in a clear way.

In the case of a hyperopic person:

Therefore, the ocular system can perform the effort required to carry on this retarded image to the retina, through a change of the power of its ocular surfaces. This is the reason why an hypermetropic person who sees wrong at distance (because her image is focused behind the retina), if she is a young hypermetropic person and/or her hyperopia is low, she has the capacity in order to focus the image on the retina and to see it clear, through her eye accommodation; this way, her visual system is constantly under “visual stress” situation in order to keep that image clear.
If also, we add the additional effort that hypermetropic person performs when she looks at their close-up tasks (since hers lens has to be more convex than the ones of an emmetropic person), in order to achieve that the image is maintained clear on the retina, in some cases it can be a really daily effort.

All of this causes some problems:

For themselves: this constant effort in order to keep the image focused on the retina, both as from a distance as for close up objects, creates stress or exhaustion in the long run, causing a certain symptomatology.

For Optometrists: young hypermetropic people are more complicated to diagnose when the refraction is small, because they are able to “consume” it, their accommodation makes up for any lens.

Well, this is only the beginning…

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Why does a myopic person’s vision improve when she squeezes her eye lids to a narrow opening?

2009-04-12T07:01:00.000-07:00

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Ref: BOOK: PRIMARY CARE OPTOMETRY

One feature of myopic people is that when they look far away and see blurred, tey unconsciously learn that their vision improve when squeezing their eyelids to a narrow opening.

The reason why this happens is because when an eye is “focused”, the image of the point that it looks to, is equivalent to a clear point; but when the eye is “out of focus”, the image of the point is equivalent to a blur circle.

In order for you to understand better, I will explain the difference between “optical image” and “retinal image”. We should begin from two premises:

Optical image is formed by the optical system of the eye. It is always clear and it may or may not coincide with the image formed on the retina.

Retinal image is formed on the retina, so it may be blurred or clear.
If the optical image is sharply focused on the retina, both images are one and the same; but if the optical image of a point object is not focused on the retina, the retinal image will be a blur circle.

The size of this blur circle depends on two factors: the distance of the optical image from the retina and the pupil size.

For a constant pupil size, the distance of the optical image from the retina (or the size of blur circle), is determined by the refractive error; the lesser the refractive error, the closer the image will from the retina, and therefore, the lesser the blur circle size will be.

In the other hand, for a given position of the optical image, if the pupil size varies (varying the brightness of the environment or squeezing the eye lids), the circle size varies too, so if the pupil size is smaller, the circle will be smaller too.

So, when a myopic person squeezes her eyelids, she just reduces the quantity of light rays that get into her eyes, and with this, she achieves decreasing the size of the circle on the retina, causing a more clear image.

It is proved that for the Visual Acuity to be good, the pupil size must range between 2 and 5 mm: when it is smaller than 2 mm, the diffraction effects of the light tend to reduce Visual Acuity; whereas if it is bigger than 5 mm, spherical aberration is the factor may reduce it.

Therefore, in order to know whether a child has myopia, a test can be performed: the child covers one eye whereas with the other eye, she looks some letters far away from her, through a cardboard with a small hole of around 1 mm (it is like a homemade “pinhole”). If the child has myopia she will see better when looking through the hole (it is just as if she squeeze her eye lids to a narrow opening); if the child is emmetrope (not refractive error), she will not see any difference.

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Regarding a movie: “Blindness”

2009-03-26T02:48:00.000-07:00

Enlace a entrada en español.

A digression on the “Myopia series”.

Some days ago, I went to watch a just premiered movie “Blindness”. I will leave my personal criticism out since this blog is not about movies or books. But as a plot, for those people that have not read the book of the same name by Jose Saramago (from which the movie is adapted), or have not watched the movie, I will tell you briefly that it is about how panic and paranoia invaded a whole city when, one by one, all citizens are victims of a sudden blindness called “white illness”. The human behavior and condition give an exorbitant turn.

This novel/movie shows clearly how men are used to vision and how they give it very little importance when they own it. People that are born with vision, they do not know what they own. Fortunately only 3% of the world´s blind population are children. All of our daily activities require a good vision, from the time we wake up in the morning and we look at the watch, until we go to sleep and prepare the alarm clock for the next day. “Time concept” is very important for a blind man, that without light, has to learn to distinguish in what moment of the day he is, surrounded by that constant darkness –clarity-; in the case of sudden blindness, this causes a disturbance in the human biorhythms, and he does not know when he has to eat or to sleep.
A team of neuroscientists of the Visual Neuroscience Training Program at Johns Hopkins Institute, Baltimore (USA) has discovered (December 2008) a small number of light sensors (nerve cells) in the retina of our eyes, that communicate with the brain through very tiny and slow signals; and, unlike cones and rods, these cells contain MELANOSIN, which are not used for seeing images, but to monitor light levels in order to adjust the body’s clock and control constriction of the pupils in the eye (among other functions).

Ask yourself, what activities, simple or complex, you perform throughout the day WITHOUT THE NEED TO USE VISION… NOTHING, even when we dream, we see images. Many jobs such as computer users (a very high number of people, even those that work at home, and it is increasing), surgeons, taxi drivers, bricklayers, architects, dentists, plumbers, etc., need to have vision 100% of their time, or rather, we are used to use our vision 100% of our time.

At school, the reading and writing learning process of the children requires that 100% of the information that arrives to the brain gets in through the eyes. The school learning is purely visual. Really MEN ARE MAINLY VISUAL; human evolution has created us this way, it has created us such dependence on vision that when something like this happens and the adaptation of environment does not cause the immediate development of other senses, the first reaction of our brain is to change our behavior. In the case of the novel /movie, the change is not positive, but like in war moments, catastrophes, etc., it is proved that the human condition does not always offer its best face.

There are many people that do not like the changes in their life, regardless of whether these changes are controlled as uncontrolled (book: “Who moved my cheese”); but when you lose something that the rest of your life depends on, such as vision, this involves a change in your thinking, your habits, your hobbies, your plans and definitely your whole life.

One defect of our human condition is that WE DO NOT APPRECIATE WHAT WE HAVE.

80% OF INFORMATION THAT ARRIVES TO THE BRAIN, GETS IN THROUGH THE EYES.

This post is only an approach that I wanted to show you, in order to appreciate your vision and take care of it. Asking yourself: “What if I’d done this or that…”, always happens, but it can be late!!!!

Refractive disorders: Myopia (3). Solutions

2009-03-17T12:37:00.000-07:00

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Solutions

Myopia is not an illness, that’s why it can not be “cured”.

If you want to “compensate” a myopia or its problem of blurred distance vision, the treatments most commonly used imply wearing eyeglasses or soft contact lenses (mainly disposable ones); in order to go to the theater, to drive, to walk, to watch TV, to practice some sport,… In this case, myopia is corrected with minus or diverging spherical lenses (thicker at the edges than in the middle of the lens), that optically falls behind the image on the retina.

But if you would like to “try to stop” that progression as much as possible, the perfect thing would be wearing contact lenses and still better, if they are semi-rigid permeable ones.
Besides this, the ideal thing would be to perform a series of simple visual exercises, which mainly teach us how we should correctly use our ability of focusing (accommodation) and how we could teach our visual system to be less “focal”, so that, although we are performing much near work with papers, computer, books, notes, homework, and for many hours, we do not help myopia to keep on increasing. This is one of the visual functions that we can work with the vision therapy.

Besides all it has been said before, if the myopic person with few diopters (less 1 diopter), removes her eyeglasses in order to perform that near work, she will help her visual system (specifically, her ciliary muscle and her crystalline lens -8-, structures that are responsible for focusing works the right way) not to be stressed. In the case of a bigger myopia, she would need another pair of eyeglasses with less degree of myopia, in order to work at near with it without performing unnecessary effort. Although it is totally proved that the use of near eyeglasses with less refraction is useful in order to reduce the myopia or to stop it, it improves the environment factors without a doubt.

Many people choose the solution that “will put an end” to myopia, tired of using eyeglasses or contact lenses during much time, resorting to Refractive Surgery. This solution is given by ophthalmologists (not by optometrists). But I have to let you know that not all patients are suitable for this procedure. What I advice you is to go to a clinic specialized in this kind of surgery and that after a complete ocular exam, they advice you your best option.

In the case someone wants to “reduce myopia” without getting into the operating room, there exists the option of a treatment performed with semi-rigid permeable contact lenses, called ORTHOKERATOLOGY or “corneal refractive therapy”. This is performed by optometrists. This technique consists of leveling little by little the excess of myopic corneal curvature (when the main cause of the myopia is the cornea), until the point of best vision is obtained, and respecting the health of this ocular structure. Thereby, contact lenses can be used only when we sleep (and not all nights) and then, during the day we can enjoy good vision without wearing any refractive compensation. This option is perfect for those who candidates that need to achieve a certain Visual Acuity without refraction in the medical examination, and they do not want to get into the operating room.

Lastly, in order to “prevent” not only that myopia rises or increases, but also to avoid any symptom of visual strain, we should take into an account some RULES OF VISUAL HYGIENE, that are not detrimental to anybody, but, on the other way, can help EVERYBODY, in the carrying out of the near tasks. Again, these rules improve the environmental factors.

But I will explain all these solutions that we can offer the optometrists in later posts.

As myopia keeps on awakening many questions, research is continually performing going on in order to stop its progression and remove it. Nowadays there is an European project called “My Europia”, that is focused on the creation of special eyeglasses with different refraction in the middle of the lens and in the periphery, that causes that the eye to react different ways in order to prevent that progression.

Medicines, vitamins,… Is there anything that I can have in order to stop my myopia?

Until now, there is no medicine that can certainly works in order to stop myopia. The only thing that has been tried in different schools at USA is pirenzepine . But as you can read in the article, this medicine is able to cause myopia to progress slowly but it is not able to prevent that progression. Besides this result, there are still many concerns: secondary effects, what happens if we interrupt the treatment, or how much time would a patient need to be with it. Also, even though this medicine was safe, it had to be removed from some children because it caused ocular irritation. Therefore, there is still much research to do in this subject.

In the other hand, vitamin A, lutein and zeaxanthin are supplements that are said to help eye health. I guess this is like the rules of visual hygiene, if you perform them, they are not detrimental to you; they are vitamins and they are always good for our organism, but personally, I would not support a treatment exclusively on them.

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Refractive disorders: Myopia (2). Kinds and Factors

2009-02-25T07:02:00.000-08:00

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Different kinds of myopia, which one is yours?

CONGENITAL MYOPIA – It is the myopia of the newborn, mainly those who are born with low weight or are premature babies (“20% of preterm infantas suffer from myopia; as the greater the degree of prematurity is, the level of myopia is higher, reaching 8 to 10 diopters, according to a study by the International Center of Optometry –IOC-”). This myopia persists in the childhood, and remains when the school stage begins (6 years) (2%). It is not usually a low myopia degree and as time goes by, it will increase.

ACQUIRED MYOPIA -

Myopia caused in the youth – This myopia appears between 6 and 12 years old. This percentage increases from 2% at 6 years old to 20% at 20 years old :-O

Usually, it is a low myopia degree (-0.50 diopters or more), mainly if it appears from the age of 12. Normally these myopia will decrease, turning into emmetropia or even hyperopia in adult age.

Myopia of young adult person – This appears between 20 and 40 years old, as well in low degree, but the prevalence increases up to 30%. As the previous one, this myopia will decrease too, turning into emmetropia or even hyperopia at the last stage of the life.

These two last myopias are low and they are usually due to environmental factors (*), as for instance, excessive near-point visual activities or bad conditions of visual hygiene at school/home/work/… These myopias may increase but they will not do it in high degree.

Myopia at the beginning of the maturity – This appears from the age of 40-50 years old and the prevalence increases gradually at the last years of the life. It is the case of those people that when reaching this age, say they do not have any problem at reading a book unlike their friends of the same age. The reason is that this myopia is usually associated with the changes of the density of the ocular structures, typical of the age. When the density changes, the “refractive index” of these structures changes too, and therefore, as well the power of the whole ocular optic system. This kind of myopia is directly associated with the development and the progression of Cataracts. At a first stage myopia may be compensated through eyeglasses, but if the cataract keeps on going the natural course, the last step is surgery.

NOCTURNAL MYOPIA or NIGHT MYOPIA – It becomes apparent just in low light conditions when we want to look at a distant object. It may affect any people (myopic or not), mainly young people, and even if daytime vision is normal. Its value is usually -0.50 diopter, but may reach even -1.00 diopter in extreme cases, and in myopic people may increase the refraction at the same proportion.

This myopia is due to a disruption in the “accommodation process” (briefly, accommodation is the ability of our eyes in order to focus on different distances – I will write more about it in another later post -). When we look at distant object, accommodation does not work, so, it must be totally relaxed; but for that to happen, we need to see all details of the object so a clear image is achieved in the retina. If the light decreases, it is more complicated to see those details; so accommodation, in an attempt to clear the image, starts to work and focuses on an intermediate distance that it is not really where the object is.
Besides this, when the light decreases, the pupil is dilated (increases its size) in order to allow more light to get into the eye. But when the pupil diameter increases, the “depth of focus” (**) decreases and spherical aberrations of the visual system increase.
Because of all the previous, this nocturnal myopia is more noticed when we drive at night, since we need to see well, and we feel some insecurity behind the wheel because of this reduced vision that this myopia causes.

A little myopia of just -0.50 diopter is equivalent to losing around 15% of visual acuity, which is enough to make nocturnal driving difficult.

In the case of a emmetropic person (without refraction on daytime conditions) or a myopic person, both may solve the problem by wearing eyeglasses that correct this myopia in those conditions; in the case of the low hyperopic person, sometimes, she may remove her eyeglasses in order to drive at night and feel better; but in many occasions, the performance of some visual exercises focused to use that accommodation correctly, avoids the use of those “extra-glasses”.

Here you have an interesting article, that I encourage you to read (though it is written in Spanish) “The drivers visual acuity is reduced 70% at night”

PSEUDOMYOPIA – During many years, the progression of myopia has been researched, but nowadays there are few specific findings; as the factors are not very clear, neither what happens in the eye when the myopia increases.

Some people that say when a myopic person performs near work for a long time and a prolonged accommodation is made, a strain is carried out in the vitreous camera (9), that causes an increase of the axial length of the eye; this is why the image is not focused on the retina, but in front of it and this causes an increase of myopia.

In the other hand, others say this progression is due to a “ciliary spasm” because of a prolonged accommodation: the tonicity of ciliary muscle increases until that in a certain moment, this muscle can not get totally relaxed in order to allow seeing at distance. It is like when you take a very heavy object, and keep it strongly with your arms during some specific time, although that involves a great effort. When you let the object go, you are not capable of stretching your arms, they are rigid in that position; it is what you call “the muscle is spasmodic”. That is why, when myopia appears, or initially increases, the patient usually complains that distance vision is blurred after working at near a prolonged time, but after some minutes the vision is clear. This is called “pseudo-myopia” or “false myopia”; a real myopia does not allow that after any short time, distance vision improves. When this pseudo-myopia begins to become evident, the degree is only -0.50 to -1 diopter, this is the reason why if we can not avoid it, the best thing would be for you to receive visual therapy in order to relax that muscle, and teach your eyes to work at near without the effort that favors the increase of myopia. Thereby, we avoid that myopia to be irreversible and lastly, that an increase of the eye axial length is made, leaving myopia already structured.

MAGNA or PATHOLOGICAL MYOPIA – They are very high myopias (more than -10.00 diopters). These people should encourage periodic eye checks, since they may suffer complications as cataracts, glaucoma, retinal detachment (sudden and abundant floaters) or vitreous detachment, or macula pathologies.

(*) Factors that cause myopia

If you have always asked what you could do in order for you and your children to avoid having myopia, or even to avoid that the myopia that you already have, increases, I am so sorry tell you it is very difficult to achieve it :-(
This is because the factors that cause the myopia and its progression are nowadays a very controversial subject and have carried out much research, without finding out exactly which is the main factor: whether the hereditary character, the environment factors or both of them.

We are more worried about the progression of myopia than of any another refractive error, because, as I wrote before, although only a 2% of the children that start school suffer from it, this percentage increases very much during school stage, and also its progression is very fast during the later years. In the case that the myopia appears in adult stage, the progression is slower, but unlike other ametropias, once the myopia begins, the progression is sure. This might mean that exists an environment influence in this progression.

(**) DEPTH OF FOCUS: Until now, I had explained that in order to see an object clear, its image had to be just in the retina (fovea), but that is not totally correct. A small MARGIN is accepted, in front and behind of the retina, where the image of the object that we see, can be located, without losing clarity; this is called “depth of focus”.

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Refractive disorders: Myopia or Nearsightedness (1). Vision and Symptoms

2009-01-28T04:41:00.000-08:00

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As I wrote two posts ago, myopia is the best known refractive disorder worldwide. And that’s why, I have many things to tell you about this, so, I will need more than one post…

Myopic person’s vision

The typical complaint in myopia is “BLURRED VISION WHEN TRYING TO VIEW DISTANT OBJECTS”.

DISTANT vision:

Therefore, a myopic person placed next to this lamppost in Gran Via at Madrid, looking at distance, she will be able to focus (see clear) this nearby lamppost, but as her eyes look further, she will see in a blurred way more and more. Of course, it will depend on the degree of myopia or quantity of myopia that she does not wear (assessed in DIOPTERS –D-); a myopic person with a little refraction, will be able to see clear further than other that has more myopia.

CLOSE vision:

As with distance vision, this also depends on the degree of the eye refraction:

- If it is compensated (she wears corrective lenses -eyeglasses or contact lenses-), she sees well, but, in the case of a low degree myopia (lower than -3.00D), she will be doing an unnecessary effort with them. In the case of a medium degree myopia (between -3.00 and -6.00D) or a high degree myopia (higher than -6.00D), the optical effect of the lens will decrease the size of the letters very much, and she will need to bring the text very close.

- If it is not compensated, a person with low degree myopia will read without any problem and much more relaxed. In the case of a young person with a medium degree myopia, she will have to do much more effort than any person, but she will be able to do it; and an adult person with medium degree myopia or any person with a high degree myopia, she will see it probably blurred.

Appearance of myopic eye

- The nearsighted eye is usually longer than normal, because of the eye axial length is greater than normal (> 24 milimeters).

- In the other hand, the power of its lenses (cornea -1- and crystalline lens -8-) is higher than normal (cornea: >43.05 diopters and lens: 19.22 diopters), being its surfaces more curved.

According to these two features (and/or others), the image is not focused on the retina, but in a point in front of it, so that the image of the distant object (placed at 20 feet -6 meters-), is seen blurred.

Prevalence

Some data:
- In Spain, as well as in USA and UK, up to 25% of the population is myopic.
- In some Asian areas, such as China or Malaysia, up to 41% of the adult population is myopic to -1.00 dioptre and up to 80% to -0.50 dioptre.
- In Australia, the overall prevalence of myopia (worse than −0.50 dioptres) has been estimated to be 77%.
- However, in countries such as Brazil and India, the prevalence is estimated at 10% or lower.

In general, approximately a quarter of the adult population from Western Countries and 80% of children during school-age years, have myopia.

Behavior of a myopic people (symptoms)

Without wearing her refraction correction:

- She sees blurred at distance.

- A myopic person sees better at distance when squeezing the eye lids making a narrow opening.
- She can not see at distance but she does see very well at near: It is difficult for her, for instance, seeing the chalkboard at school or seeing a sign while she drives; however, she sees very well a book or the directions for using a medicine.

- She sits very close to watch television, computer or chalkboard.

- She brings the writing, reading, painting, drawing, etc., very close to her eyes; it is like if she were eating the paper or what she is looking at, mainly if the myopia is high.

- If the myopia is low, she can work at near in a more comfortable way and for more number of hours without getting tired.

That’s why, they prefer activities as reading, drawing or handicrafts, that is, any activity at near.

- They are shier and more absent-minded, since they are very “focal”, that is, they are not very aware about what surrounds them; they are able to concentrate very much and to be many hours performing a task, so that the world can fall surrounding them and they do not realize, neither whether it gets dark or not, nor whether anyone has arrived at home or not, nor whether it is already the dinner time,… This ability to concentrate (that others, as a hyperopic people, envy), acts against themselves, because, it favors the increase of the myopia, since they do not rest even to have a glass of water. This ability allows them to be good workers and to have a good school/labor performance.

- Related to all previous, they have a reduced peripheral awareness, due to as the “excessive” concentration, as well as to the close working distance that they use sometimes without realizing.
For instance, when they are reading a book, they bring it closer more and more, because, this way, the letters seem bigger. But, in one specific moment, the eye movements are not enough and they need to move their head to be able to read a whole line. If they try to get away from the text, the letters “seem smaller” (therefore, more uncomfortable for them), but the visual field increases and they are able to read faster, because they can cover a whole line just by having a look.

- Sometimes they suffer headaches (mainly in forehead and temples) or eyestrain, and sometimes, they might even squint noticeably when they are physically tired.

RELATED POSTS
Refractive disorders: Myopia (2) Kinds and factors
Refractive disorders: Myopia (3). Solutions
Why does a myopic person’s vision improve when she squeezes her eye lids to a narrow opening?
Refractive visual Disorders. Some clarifications.
Some numbers...

Some numbers...

2008-12-29T10:54:00.000-08:00

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Extracts of the Presentation to the International Society for Geographic and Epidemiologic Ophthalmology by David Dunaway and Ian Berger (InFOCUS Center for Primary Eye Care Development).

[…] Estimates of the number of people worldwide with refractive error range from about 800 million to 2.3 billion. No prevalence data are available from the World Health Organization or from any other source relating to very large populations such as groups of nations, or whole countries. […]

[…] As for the proportion of an entire population with refractive error, Daniel Etyale of the W.H.O. reported at a special session on refractive error at an International Agency for Prevention of Blindness meeting in 2001, that 5 -15 percent of children are considered to have refractive errors, the majority of which are uncorrected, and that there is currently a need for population based studies to ascertain these figures. […]

[…] Although sufficient data have not been collected to accurately predict prevalence per diopter of correction for most populations, general prevalence information on the three types of refractive errors and of presbyopia can provide an orientation of what to expect.
- Hyperopia, for example, is usually present at birth, except in premature infants. Hyperopia decreases in magnitude through age 4 years, and the prevalence of hyperopia less than +1.25 D (an amount usually difficult to compensate accomodatively) is 4-7 percent between ages 5-20 years, remains constant through early middle age, then increases in populations aged 45 or more. […] Hyperopia also occurs in patients with poorly controlled diabetes and in patients who've had cataract surgery.
- Myopia prevalence varies with age, race and sex, increasing at least through adolescence, and is present in 1 per cent of children at age 5 years, increasing to 8 per cent at age 10 years and about 15 per cent at 15 years. Myopia occurs slightly more frequently in females than in males.
- The prevalence of astigmatism may be as high as 70 per cent, if all amounts are included, but is considered to decrease to 3 percent if the extent is limited to 1.25 diopters or more. […] If astigmatism is greater than 1 diopter, it usually develops before age 2 years.
- Not a refractive error, presbyopia is due to a loss of accommodative ability. It usually starts between ages 38-45 years and the prevalence is 100 percent by age 55. Early onset is associated with hyperopia. […]

RELATED POSTS
Refractive visual disorders. Some clarifications.

Refractive visual Disorders. Some clarifications.

2008-12-11T13:09:00.001-08:00

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As I wrote in the previous post, when we assess somebody’s Visual Acuity and the result obtained is not 20/20, it may be, among other reasons, because of the presence of some “ametropia” also called “refractive eye disorder” or “refractive error”.

But before explaining what these words mean, first I will explain what Ocular Refraction is: it is a physical phenomenon where the light rays from the object that we look at and from the whole visual field surrounds it, when crossing certain optical structures of the eye, change their path to focus on the fovea (13) and certain points of the retina. There, these light stimuli are converted into nervous stimuli which are sent to the brain (occipital lobe) in order to convert the information from the both eyes into simple and clear image of the target and all that surrounds it.

This change of the light path is mainly due to two structures which act as lens into the eye: the cornea (1) and the crystalline lens (8) . And to a lesser extent: the aqueous humor (4) (in the anterior and posterior chamber) and the vitreous body (9) (inside of the vitreous chamber), which also influence the “dioptric power” of the eye.

Therefore, when the image of an object, placed at 20 feet (6 meters), is focused on the retina of an eye, it shows that this eye is emmetrope and its Visual Acuity (if it does not have any pathologic disorder that hampers it) will be 20/20 or better. That is, this eye does not suffer any refractive eye disorder.

But if the two following conditions are fulfilled:
- its Visual Acuity is lower than 20/20
- and it improves with the help of eyeglasses, contact lenses or another optical option,
then we can catalog this eye disorder as “Refractive Error” or “Ametropia”. This disorder is due to an upset in the power of either one of or both lenses (surfaces more curved in the case of the myopia and more flat in the case of the hypermetropia), or a change of the eye axial length (the eye is too short in the case of the myopia and too long in the case of the hypermetropia):

Grosso modo, I will now explain the refractive eye disorders, but in later posts I will explain each one of them in detail.

MYOPIA: It is the refractive error that is better known, worldwide. This prevents the distant objects to be clearly seen. In this case, optically, the light rays from the distant object (placed at 20 feet -6 meters-), are focused in a point in front of the retina, so the image is blurred.

HYPERMETROPIA or HYPEROPIA: This refractive error prevents the nearby objects, and sometimes the distant ones too, to be clearly seen. In this case, optically, the light rays from this object are focused in a point behind of the retina; so, as with the myopic eye, the hypermetropic one also sees the image blurred.
But the difference with the myopic eye is that this defect of vision is more unnoticed, and it is a defect no so well-known by people, because of the modifications that the crystalline lens can perform of its curvature, so this lens can compensate part or all of this hypermetropia ( if this is not very high) so it remains latent.
It is the most common refractive error in the newborn, because when the baby is born, the eye is not completely developed and as the body grows, so does the eyes. So, a baby with a small hypermetropia may turn into an emmetrope when she grows.

ASTIGMATISM: In the previous refractive errors, the cornea is a spherical structure (as if it was an inflated basketball that we have cut in half). However, in this defect of vision the cornea can be seen as an American football also cut in half.
Therefore, each curve in the cornea has a different dioptric power (I will better explain this concept later) and consequently, the light rays that cross each curvature suffer a different change of direction, and causing a focusing of the image on different points regarding to the retina, causing not only a blurred image but also a drop-shadow effect in the surroundings of the distant and/or nearby images. Because of this reason, the astigmatism can co-exist with myopia or hypermetropia in the same eye, but these last errors can not co-exist in the same eye at the same time.

All these refractive eye disorders cause a “faulty vision”, but in these cases this is only due to a wrong Visual Acuity. That’s why, VISION and VISUAL ACUITY are not the same concept, because we can have a value 20/20 of Visual Acuity and not being able to read the registration number of the car in front of us at 2 meters (6 feet) or keep on reading for 1 hour. Visual Acuity is only one of the different features of vision.

These “ametropias” are primary; secondarily, other refractive eye disorders may also arise:

ANISOMETROPIA: It is very strange to find a person with the same quantity of ametropia in both eyes (because we do not have two identical eyes), but anisometropia is the condition in which this difference is so big, that it is difficult that the information from the images from each eye that arrive to the brain, can be fused (I will explain this better) and can create a simple clear image.

AMBLYOPIA: It more well-known as “LAZY EYE”. This may be related to the previous disorder. I am sure some time you had seen a child wearing a patch at school or in the street, since this is one of the many ways to treat this problem (I will explain this one too).
In this case, the difference of eyeglass prescription and the functional features of one eye may be very different from the other, so one of them develops better. In this case the early diagnosis and treatment is VERY IMPORTANT.

PRESBYOPIA: Sooner or later everybody will “suffer” from this ametropia, even the person that think that, while being young, has got the best vision of the world… Sorry
This is just because of the natural aging process of human body. As time goes by we keep on losing our forces and things we could perform some years ago, now we are not capable of doing them; in vision the same fact happens too. Inside the eye, the muscle that controls the change of focus for different distances, by modifying the curvature of crystalline lens, “is more tired” too and keeps on losing flexibility, force and speed of response. As time goes by we have more difficulty for focusing more quickly and we can not see small details of nearby objects. The arms seem to stretch more and more and we would wish we’d have them longer in order to read a medicine directions for use or just a newspaper. In this case, the problem we have I resides in nearby tasks.

In the other hand, there are other disorders that also cause reduced Visual Acuity, but the difference is that this value can not be improved with any optical option, they are not refractive eye disorders but pathological disorders: Cataract, Macular Degeneration, Glaucoma ... In these cases the required treatment can not be offered by the optometrist (medicines and surgeries).

Besides there are defects of vision that are independent of the Visual Acuity value, such as, for instance: a reduced visual field, a disorder of color vision, a problem in order to focus in an efficient way when we read a book, or to work with both eyes as a team, or to discriminate shapes, or to remember what we see, or to copy something we see, or to follow a straight line… Therefore, these are not disorders of the Visual Acuity.

ILYD

A good vision is not only seeing 20/20

2008-10-29T05:21:00.000-07:00

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Just as “seeing” is not the same as “looking”, talking about vision it is not only enough that light focuses in a specific point of the retina in order to see 20/20, but also, vision is understanding what we see.

In order to understand this concept, I will firstly explain what the words Visual Acuity mean, that many times we utilize them with our patients when we say “You have 20/20 vision“, but maybe you are not quite sure what actually that means.

When we assess the Visual Acuity test, we are assessing the ability that someone has to identify some letters or patterns from a distance where they should be seen; and the final value is the smallest symbol size than the patient is able to read from that distance.

Let me explain it better: when we perform this test, the patient must sit down 20 feet (6 meters) away from the letters chart. When we say that a person have 20/20 visual acuity (100%, 1.0 or 6/6, everything is the same), what we mean is that the person sees 20 feet away from the chart what she should actually see 20 feet away. But for instance, if that person has 20/10 visual acuity (6/3 or 0.5), that means she would only see from 20 feet what she should see from 10 feet, that is, she has 50% of vision.

Therefore, Visual Acuity is the ability to see the details of an object. But precisely because that object is not floating in the void, but furthermore, there are many more objects surrounding it, we are in a distance from that object, we may want to execute an action with it and other senses may be implicated in this action…, vision is just not only clearly seeing that object, but that many more “visual qualities” might be implicated, as we saw in a previous post .

“It is estimated that as much as 80 percent of all learning during a child’s first 12 years comes through vision”.

Because a child or an adult has 20/20 visual acuity according to a certain test, it does not mean she has good vision, since she may have problems in order to focus on a text when she reads a book, or may have bad eye-hand coordination and consequently have a bad writing, or may have some problems to how her eyes work as a team and they feel tired 10 minutes after they start a near task, or may be "clumsy" and hit herself with things because she does not calculate the distances well. In all of these examples, vision is involved and with them I only wanted to show that although we have a 20/20 Visual Acuity maybe we do not have a 100% Vision.

In many optician’s, when a person goes to check her vision, they only obtain this result and only find out the lens required to improve that percentage (whether there is myopia, hypermetropia or astigmatism), without assessing if that vision works well and if it works along with the other senses. That is, for them the goal is to obtain 20/20 visual acuity and they do not think in any other symptom that shows that it is not only important to improve Visual Acuity, but also to improve the performance working at near, or practicing a sport or reading and its comprehension. For it, as the daily problems are not always related to a visual problem, I recommend you to go to a specialized office that offers you a broader eye examination. You would be surprised of how many symptoms and problems at school can be removed by using Visual Therapy, and what this can be done to improve the quality of life in general of any person.

A child may be diagnosed with a “perfect vision” by an optician or an ophthalmologist (it doesn’t matter) simply because she has 20/20 visual acuity, but without being assessed the necessary visual skills (focusing, peripheral vision, eye-hand coordination, discrimination of shapes, spatial relations,…) required to have a correct learning or a good physical coordination. In a later post I will thoroughly explain the visual problems related with learning.

If a child is struggling with academics, sports or home behavior, parents and teachers should be encouraged to consider that a vision problem may exist, beyond a Visual Acuity.

A simple comparative example is the following one: when we read, it is not enough to verbalize what we see written and to read as a parrot, we have to understand what we see. Therefore, when we read, we must not only clearly see the letters, but we have to know, to remember, to interpret and verbalize what is written; vision process is responsible for all this.

So, after all this, mi goal is for you to have a clear understanding that when you go to an office or optician’s, the Visual Acuity assessment must be ONLY a value obtained of the whole visual examination in order to achieve a precise diagnosis.

BOOK: "20/20 is not enough"

An apple a day really does keep the doctor away

2008-10-06T05:36:00.000-07:00

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This idiom is very famous, but we do not always heed this advice.

Prevention and Early Detection

Optometry basically detects visual upsets, that is, visual problems, performance problems related to vision, development problems related to vision, and so on. Therefore, if this detection is made as soon as possible, the treatment will be more effective, will need to carry out it less time and the results will be more lasting.

How can you know if you suffer any visual upset?

FROM THE FACT THAT THERE IS NO OCULAR PATHOLOGY OR ILLNESS, if you notice that you have some troubles in order to see at distance or at near (in order to read, write, draw, watch TV, drive, practice any sport, use a computer,…), this indicates that probably, you are suffering from some “refractive error” (myopia, hypermetropia, astigmatism, anisometropia, presbyopia... concepts that I will explain in later posts). These visual problems are not pathologies or eye illness, but they may cause a big discomfort performing the tasks of daily life, although they have an insignificant value.
These problems are “quantitative visual disorders”, and using a prescription (eyeglasses, contact lenses or prisms), usually they are corrected (THOUGH NOT REMOVED).

But, in the other hand, there are other “problems of quality vision” (they are not eye illness neither), that we can not be shown to the patient with understandable quantitative data, but that, however, may almost cause more frustration and powerlessness than the previous problems. This is because many people do not know very well what happened, or where they can go with their problem.
Fortunately, there are more and more optician’s shops or offices where they perform visual exams are more complete than a simple ocular refraction in order to obtain those “refractive errors”. There they detect the reason of it: a performance problem at work or at school, a learning disability, a visual development problem, a clumsiness or balance problem, an inability in order to read a book during long time, a carsick, a dyslexia, and so on. I guess that you did not imagine the great relation that there is between vision and all things that we do daily; and many times you do not realize that, by treating a problem from vision, we can solve the visual problem and the trouble that you did not know how “solve”.

What can you do if you have a visual problem?

If you have any of these problems or any other that you think that can be related to vision (if you have some question, you can consult me about it in the comments, in order to confirm if your problem is or not a visual problem that any of my colleagues may diagnose; I am sure that many people have your problem too, and if I advise you, we can help more people; but how I wrote in the welcome post, I will never give you a solution or treatment for your problem, because I would need to assess each case in an isolated way), I recommend you to visit a qualify optometrist and you ask him a comprehensive visual exam. Afterwards, he will give you the better treatment option (refractive prescription, vision therapy, reflexes therapy or rhythmic movement therapy, syntonic phototherapy... – treatments that as well I will explain at length in later posts-), or will refer you to the professional best fitted to treat your problem.

A small problem is always easier to treat than a big problem.

Identifying signs and symptoms for a visual problem

2008-09-22T06:01:00.000-07:00

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Detection of visual upsets, mainly in childhood stage, is done when we observe and assess the child’s attitude and behavior when he performs a task.

- Itching, stinging or watery eyes

- Blinks or rubs his eyes a lot
- Frowns or scowls in order to seeing better
- Blurred vision at distance or at near

- Rigid body or moves his head forward or backward when reading or looking at a remote object
- Very close distance when watching TV, writing or reading a book
- Has difficulty for copying from the board
- Unusual eyestrain when finishing a task or decline in the reading after long periods
- Omission of tasks at near
- Fatigues quickly during reading, writing or drawing
- Bothered by the sun and lights changes
- Headache and eye pain
- Negative behavior at school or at work
- Bad head or body posture
- One eye drifts or aims at a different direction than the other (look carefully, this can be subtle). This is significant even if it only occurs when the child is tired or stressed
- Closes or covers an eye, or twists or tilts head, when reading and writing or watching TV…
- Double vision

- General difficulties at Reading:

Moves head when reading instead of to move the eyes
Words slide together
Reading speed below chronological age
Does not understand what he has read or does not remember it
Loses place, skips lines or rereads words or lines
Needs to use finger as a marker to keep place
Reads in loud voice or moving lips
Omits or adds words or tries to guess them from the fast recognition of one part of them
Mixes syllables when reading and numbers in maths
Reverse letters, syllables or words
Avoids reading or other close-up tasks

- General difficulties at writing or in the hand’s motor skill:

Irregular and changeable letter size
Small spacing
Inability to write in a straight line
Reverses letters, words and numbers when writing or copying
Favors the reading with regard to playing or motor activities
Favors oral exams with regards to the written ones
When coloring, he can not keep his work inside the lines
Does not like to draw
Grabs the pencil badly, or takes out his tongue or does strange gestures with his face when he uses his hand to perform something that requires eye-hand coordination
He is slow when he has to follow a dictation

- Difficulty to comprehend and perform instructions
- Bumps into things
- Sometimes he appears clumsy
- Becomes easily distracted
- Has a short attention span and needs a lot of rests
- Poor concentration
- Homework takes longer than it should
- Poor visual memory
- Negative and/ or aggressive character
- Troubles for adapting to the changes
- Gives up easily (says “I can’t”, before trying)
- Dizziness, nausea or motion sickness
- Poor posture when sitting down and working
- Incapacity of being kept sat down on a chair more of 5 minutes
- Walks on tiptoe
- Balance troubles
- Confuses right and left in himself and/or in the space past age 7 (and sometimes up and down)
- Poor performance of sports or coordination of hand-eye and foot-eye (ball skills and team games): catching and hitting a ball
- Etc.

These manifestations will help you yourself to detect if any child, in your environment, may have an undiagnosed visual problem.

Moreover, in the optometric office, the professional will give you or ask you a brief questionnaire about the child, his development and his visual habits. Sometimes it is very long and tedious or even sometimes, you do not know what relation, some questions may have with the eyes or with the problem that you bring to the office; but there is not random question in these questionnaires, all of them give very important information that will help the optometrist to achieve a better diagnosis about the problem that the child has got. Therefore, even though everybody thinks that their children are wonderful and perfect, think that if you go to the office is because you suspect something, and if so, being as sincere as possible when you fill in these questionnaires is better, because the lies and half truths or half informations or underestimating the details that show where the child is not so handy, will not help; this information is the most valuable in the questionnaire.

RELATED POST
An apple a day really does keep the doctor away

Back to School!!!

2008-09-04T11:34:00.000-07:00

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When September arrives everybody begins our “school year” –not only children-, whether we went on vacation in June, July or August, or even if we did not leave. In summer, all of us reduce our rhythm of work; the good weather, the heat, children without school, emptier and more peaceful cities, allow us to enjoy our time much more and to calm down from the frenetic rhythm of the rest of the year.

Therefore, our visual system is much more relaxed, since if our work stress decreases, as well as our visual stress decreases. On vacation, if we read is because we want to do it, or if we perform some task at near is because we are getting back to some forgotten hobby. In any of these cases, the strain is minimum and we rest when we want. So, this is the best month to check our vision. This vision will be in its purer and more relaxed state, it will give more real values both in quantity and quality of vision (refraction, focusing, fusion, perception, visual acuity, integration into other systems,…); moreover, in an emotional way, everybody is more relaxed when we are back from vacation, and everything affects.

Consequently, before going back to the intensive rhythm of all year, it is recommended to receive a complete visual exam to check that everything is right or in order to give solutions if there exists any problem before the symptoms arise, or simply in order to receive a guide from the optometrist about some good Rules of Visual Hygiene and/or of Relaxation; these are not bad things to do (I will give this rules in another post later).

The particular case of the child

But if checking that the visual system is in full performance (with nothing that disturbs it) is important in adults, imagine how important this is in the case of a child, where any visual problem can make it difficult for his right learning when reading or writing, in his hand-eye coordination, in his motor development or in his balance when he practices any sport, in his perception, in his integration of the visual information with that of other senses,… All of this will create social limitations that will be detrimental to his development, his personality and his character.

The child is in constant development and any obstacle appeared during it (in this case I write about visual development, but he would be affected by any upset of any sense that provides information that he has got to integrate), may disturb all visual information processing. It may disturb:
- the way information is received,
- the way information is integrated,
- the way information is processed,
- or even, the way received information is answered,
doing any of these actions FROM A WAY DIFFERENT THAN THE REST OF CLASSROOM CHILDREN; so, any school or daily activity (even playing with his friends) may require from himself the following: more effort, more time, more energy that makes him feel more tired, more concentration that actually makes him easily lose it when he is tired of maintaining it, more support from other senses or other skills that makes him carry certain activities in an out of balance way, and so on.

Between 0 and 14 years old detecting and treating any visual upset is very important, since constant anatomical and physiological changes are happening in the visual system as the child grows up, making the visual patterns and all neurological connections that will affect his future Perception. Also, in the first years of life, the child is learning from everything that is surrounding him, from everything that he does, and as I wrote in another post, much of this information gets in through the eyes. One visual problem (WITHOUT BEING A PATHOLOGICAL PROBLEM) may cause:
- academic performance problems,
- sport performance problems,
- school failure (to long-term),
- and the worst, self-esteem problems.

Once the visual problem has disappeared (it has been treated), these schoolchildren will improve their grades, will be happier and will be more social. They will feel with capacity to face difficult challenges in their school stage.

This is the reason why an EARLY DETECTION is so important in these ages; and both parents and teachers are responsible for detecting any small problem that the child has when he makes his daily tasks. The child will never complain because he does not know what a vision problem is, and he thinks that everybody sees like him, and if his schoolmates obtain better grades than him or play football better than him, he will simply go make a negative opinion of himself (“I am more stupid or more clumsy than the rest”), reaffirmed by the environment many times, without knowing that there is “something” that hampers him from being in the same conditions that the rest of his schoolmates or friends when he performs any activity.

One out of three children in school age suffers some kind of visual problem WITHOUT DIAGNOSING, and around 25-30% of school failure is related to visual upsets.

In the next post I will give you a list of signs and symptoms that we may take into account to detect whether your child or your pupils have some visual problem (some of that symptoms will as well valid to for the adults), but a summary, any visual problem may cause the following problems to a child:
- he can not attentively follow the teacher’s explanations in the blackboard if he does not see very well at distance,
- he can not read and study comfortably if he does not see well enough at near,
- he can not understand what he reads if he has to strain in order to read correctly,
- he will reject to go to school on a constant basis,
- his behavior will be absentminded and it will take him a lot of hard work to focus on any activity that requires a big attention,
- he will not like doing his homework,
- he will gradually feel isolated and retarded from the rest of his schoolmates with regard to his learning,
- therefore, he may make himself introverted or even develop an inferiority complex, very negative for his development as a student and as a person.

Many times parents and teachers blame these negative attitudes to psychosocial problems, to reading and writing problems (dyslexia) or to hyperactivity, when the most probable cause is just because of visual problems that have not been treated.

Although a child had not developed his visual system in a normal way, the sooner we detect the problem, the sooner we will be able to treat it and to help him promote his visual system, getting back to his normal development level for the child’s age. This happens because the younger the child is, the more plastic his visual system is, due to that although the visual organ develops completely at 2 years old, until 5 years old his visual system is not completely functional. So, if during this period his vision suffers any upset (myopia, astigmatism, eye deviation, lazy eye, retained primitive reflex,…), the development will not be the same, and if it is not treated on time, it will cause difficulties in his daily life. We can not allow for the time to go by and see if the problem is solved by itself, BECAUSE THIS WILL NOT HAPPEN, it will increase and it may be too late when we want to do anything.

Also, it may happen that, currently, the child has not had any problem at school and we think that his vision is perfect, and his parents decide that he does not need any visual check WHILE HE DOES NOT SHOW ANY PROBLEM AT SCHOOL. We must not wait for this moment to happen: a routine check is not bad for anybody and it can avoid that the symptoms and the performance problems at school rise. It may happen that in previous academic years the child had no problems, but as the new year passes by, he shows performance problems or bad grades that he did not have until that moment. That may simply mean that the child has a latent visual problem that was not obvious until that moment because the academic demand was not sufficiently high to show it. But when the academic demand increases, the level increases, and a visual problem that seems in control is suddenly out of hand. For instance, because the effort for understanding a more complicated text may show a reading problem that it seemed it did not exist before.

Owing to all these previous facts, as an optometrist I recommend that all of us should receive a visual check at least once a year, CHILDREN SPECIALLY. And when I write “visual check” I do not simply mean going to an ophthalmologist – which is also recommended, in order to be sure that our eyes are in a healthy state-, but to a qualified optometrist capable to assess if his visual system is ready for working in full performance.

Any visual upset in children or adults, causes our vision not to be efficient and, consequently our learning or work will neither be.

And again in Spain…

2008-08-26T01:19:00.001-07:00

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I resume the posts after not being able to write in this blog during more than one month. The reasons have been, in one hand, that I’ve moved to my country again (our American adventure, after one year and a half, has finally finished :-( ); and in the other hand, that some serious family problems are taking all of my time. Because of this last reason, I hope I can recover the publishing rhythm, but if my articles take a long time to be posted, do not think that I have forgotten the blog. I enjoy writing it, and if nothing stops me, I will write as soon as I can.

What other types of information get in through our eyes?

2008-07-21T15:08:00.000-07:00

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Besides the four important routes that the visual information makes to process it (and that I already showed you in the previous post), there are certain stimuli that get in through the eyes and also that go to other nervous system pathways to cause the right answers.

EXAMPLE 1:
When we get across a tunnel, we turn on the car headlights on, but even so, our eyes have to get used to the sudden decrease of the light in order to see clearly again, and drive safely.

In order to achieve this action, this information arrives to the PRETECTUM (a structure in the mesencephalon next to the Superior Colliculus). This structure sends the information about “poor light”, to the EDINGER-WESTPHAL NUCLEUS and from there, finally to the CILIARY GANGLION. This last structure sends a command to the DILATOR MUSCLE of the iris, in order to increase the pupil size (i.e. it dilates), and so, to get more light into the eye. Thus, the rods of the retina are stimulated, and they give us the information that we need in order to keep on driving in those conditions.

When we get out the tunnel, the process is shorter. The information about “much light”, stops in the EDINGER-WESTPHAL NUCLEUS, who sends a command to the SPHINTER MUSCLE of the iris in order for the pupil to decrease its size (i.e. it contracts), less light gets into the eyes and therefore so we are not dazzled at all so we can see clearly quickly.

EJEMPLO 2:
The “STOP” sign one: Everything gets inside through the eyes, but as I explained in the previous post, the Lateral Geniculate Nucleus (LGN), is responsible for filtering this information so that the brain is not saturated with unnecessary information. So, the ATTENTION is involved in this process and that “attentional window” is controlled through another nucleus placed in the Thalamus: PULVINAR.

There are two routes: in one hand, the route that “facilitates the attention” and that leads it to one or another object (the STOP sign, the white line, the car in front of us…) or increase its attention range (we pay attention to everything surrounding us, to what is the car that has priority to get out of the STOP sign cross in the first place,….). And this information passes through the Pulvinar.

In the other hand, the route that “inhibits the attention” (children playing in the car behind, the shopping bag that falls over when we press the brake,…). This route is direct between the Lateral Geniculate Nucleus and the Occipital Lobe.

These routes are MAGNO, that is, unconscious routes. Fortunately we do not have to control consciously everything at the same time and many of previous routes: if we had to, a simple “STOP” sign will be chaotic.

But besides these examples or these nervous structures, there are many others with the same importance, that are also involved in this visual information processing.

For instance, the CEREBELLUM. It is the structure responsible for the coordination, the balance and the movement; therefore, it allows us to do precise movements in order to position the car right before the white line, put our hand on the wheel, put our foot on the brake pedal,…

Another example is the HIPPOCAMPUS. It is a structure located in the medial temporal lobe and is structure responsible for long and short term memory; therefore, it allows us to remember what the traffic sign means, what we have to do before it, what streets we have to take to arrive to our office, what breakfast we had breakfast this morning,…

As you see, when we are driving a car it is not only important the “what” but also the “where”, that is, we not only see the sign and see it clear, but also to need to know and interpret it: recognizing it, identifying it, remembering it, relating to the rest of information that we have, ignoring whatever it does not contribute, knowing how to act before it, knowing what we can or must do, how long and where we can move according to where we are,…

That is, in order to drive a car, to play tennis or just to walk or to move from one place to another, if we only have a picture of the things that we see, our brain can not make those judgements that are so necessary.

RELATED POST
Where does what we see go? - Visual Information Processing (from the eye to the brain)

Where does what we see go? - Visual Information Processing (from the eye to the brain)

2008-07-14T14:41:00.000-07:00

Enlace a entrada en español.

I am sure much of you think the image stops in the eye, that is, that this is where the process ends. We see with the eyes, don’t we? But maybe, after you read the previous post, your thoughts are confused.
In the other hand, I am sure some of you know that the brain is involved in this process but you do not know or understand very well how the connection is between eyes and brain.

It is true that this process is complicated ENOUGH, that is why, so it is easier to understand, I will show how what we see is processed from a practical example and with some graphics.

Let’s suppose we are driving on a street and we are arriving to a cross. In the corner we see the “STOP” traffic sign.

I am going to show you how much information is processed just when seeing this simple traffic sign.

- In the first instance, we have the VISUAL PROCESS itself, that is, obtaining the clear image.

If you remember the previous post, the image created in both eye foveas is processed by the cones (A) that are in the central area of the retina. They send the information to the parvo ganglion cells (C) and leave the eye across the optic nerve (11) . These ganglion cells take the information about the color, bright, clarity and contrast of the STOP traffic sign to the LATERAL GENICULATE NUCLEUS. This is a relief and control station in the visual pathway: almost all information -that the parvo ganglion cells receive-arrives here, and this structure filters and leads it towards the respective places in the brain. So, only ten percent of this visual information is sent to the OCCIPITAL LOBE or VISUAL CORTEX, in order to create the image.

This particular process is incredibly much more complex, but by now, this is enough to understand the rest of the visual information processing

______________________________________

The rest of the pathways that take part in this visual information processing, are not called “visual pathways”, because the information does not go to the occipital lobe directly. The following information that is processed, is not purely visual, although the information had been obtained through the eyes.

- Therefore, in the second instance, we have the following PROCESS: EYES -> SUPERIOR COLLICULUS -> PARIETAL LOBE. In this process the information about “Where am I?” is obtained:

This pathway is made up basically of magno ganglion cells (C) that received the information from the rods in both retinas.

The Superior Colliculus is a paired structure of the nervous system placed in the mesencephalon (2) , right under the thalamus. The Superior Colliculus belongs to the Brainstem, which is the structure that joins the Brain and the Spinal Cord.
It deals to integrate the visual input with the auditory, somaticsensory (about balance and proprioception, among others) and tactile input; and thus we achieve the information about “Where are we?”.
In order to answer this question, the Superior Colliculus makes eyes and head move automatically towards the stimuli in the environment.

In the practical example, the group of all information is processed so that the Posterior Parietal Lobe allows us to calculate our movement, the speed of our car, the strength that we need to do in order to put our foot on the brake pedal, the direction of our car, or the rest of the cars, where our feet are, where our hands are, where we have to stop near the traffic sign… This lobe give us a metal spatial map about ourselves.

Therefore, when we have a car crash with a collision from behind, our head suffers a “lash” front to back, and in this case, the part of the brain is usually is affected is the mesencephalon, so, as well as we suffer strong cervical pains after the accident, it is also frequent to suffer disorientation, poor concentration, panicky feeling in places with crowd or difficulty for going up or down stairs. These are symptoms that seems light and that many people might not attribute to the car crash, but they make their daily life difficult. We can help these people by using Vision Therapy to get back the lost stability back.

- In the third instance, we have the following PROCESS: OCCIPITAL LOBE -> -> POSTERIOR PARIETAL LOBE. In this process the information about “Where is the object?” -the traffic sign-, is obtained:

The information from magno ganglion cells that arrives to the occipital lobe, does not stop here; some of these mango ganglion cells (C) go to Medial Temporal Lobe and, from there, go to the posterior parietal lobe to give us some information about “Where is the stop?”: Where is the line? Where must we stop? Where is the brake pedal to put our foot? Where is the car behind us or in front us?... As I explained above, Parietal Lobe allows us to make special calculations, as in the previous process. This lobe gives us a mental spatial map about our environment.

The information about “Where am I?” and “Where is the object?” allows the parietal lobe to make a motor plan, that is, “how we must do the things”. This lobe allows us to look at the road in the mean time: we look at the mirrors, we turn the wheel if it is necessary, we keep on the security distance regarding the front car, turn on the headlights if we get into a tunnel, we talk to another person in the car, we listen to the radio,...

But if you think about it, this process is carried out unconsciously, that is, all information that comes from the peripheral retina (Magno system) is processed and is carried out automatically. The same thing happens when we are driving on a road and we find an obstacle in our lane; then we look at the rear mirror and if there is not any further risk, we slightly turn the wheel to avoid it.
The responsible lobe for carrying out this action is the parietal one, but we have to do that unconsciously, as a reflex.

When we want to pass another car in the road and we have another one in the opposite direction, this lobe gives us some information about the following: what speed is the other car going at? What speed is the front car going at? What speed is our car going at? What car is moving faster? Do we have enough time to pass without risk?...

- Finally, in the fourth instance, we have the following PROCESS: OCCIPITAL LOBE -> INFERIOR TEMPORAL LOBE. In this process, the information about “What is the object?” -the traffic sign-, is obtained:

Some of the information that arrives to occipital lobe through the parvo ganglion cells (C) from both retinas, do not stop here, they goes to the inferior temporal lobe in order to give us information about what we are seeing: the ”STOP” traffic sign. This information helps us identify what we see: it is a traffic sign, what kind of traffic sign is or what it means; and thus we can know how we have to answer (according to our experience).
This lobe is responsible for the language, that is why, it helps us to give a meaning to the things.

________________________________________

These are the four basic routes, but many others are created in the brain at the same time. I will show some of them in the next post, that it will be posted sooner than usual.

As you see, the brain is so complex and I have just showed you one part. But among many strange names of nervous structures (that I repeat, you do not need to remember), what I want you is to realize that in a few seconds, our brain works 100% and that there are maaaaany activities generated inside; this way, it is able to very effective receive, process and answer from what we see if the visual information processing is correct.

RELATED POST
What other types of information get in through our eyes?

A little bit of basic ocular anatomy… The Retina.

2008-06-25T12:27:00.000-07:00

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As I wrote in the first post of this series about “Basic Ocular Anatomy”, the retina (10) is a layer of the eye that deserves one blog post just to itself.

It is the most important layer of the eye, because it contributes to the first part of the Visual Information Processing that we receive: the formation of the image, which will be processed later on.

I am going to show the retina from different points of view, in order for it to be easier to understand. Its importance is appropriate to its complexity.

In one hand, in order to understand how the eye works, you must think about it as an “old picture camera” (that is, with film ;-)); just as the image is expressed in the camera film, it is expressed in the eye retina.

In the other hand, you must also think that the eye behaves as a “dark chamber”; this consists for example, of a dark box which has a little hole in one of its walls (as the pupil in the eye). In opposite wall (as the retina in the eye) an inverted image is made from the external objects.

One eye without any problem of refraction (myopia, hyperopia or astigmatism), that looks at distance (more than fifteen feet), is at a state of rest. The iris (2) behaves as a camera diaphragm, whose contraction controls the quantity of light that gets into it through the pupil (3); in this situation, the lens (8), the other dynamic part of the eye, is at rest. Therefore, the human eye does not have to strain when it looks at distance.

When one person looks at near, if these dynamic parts of the eye do not modify their state, he will see blurred. It is the same thing that happens if the lens of a camera does not modify its focusing in order to clear a close object (after focusing something that was far): the picture will be blurred.
In the eye, in order to clear a close object, the thickness of the crystalline lens (8) varies. This mechanism is called accommodation, but I will write about this later.

When we look distant something as well as close something, this has to get to the film inside of a camera, or to the retina in the eye, in order to achieve a clear image.

Once you have understood how the eye works, now I am going to show you how the light gets into it, and it reaches the retina (10):

The light thrown by one object converges on the cornea (1), passes through the pupil (3), and gets to the crystalline lens (8). At this point, the image is inverted (according to the optics laws). If there is no reaction in the lens, the image that reaches the retina(10) can be more or less blurred, depending on the distance to the object (considering that this is not further than fifteen feet, as I explained before). That way if the image is blurred, this information gets to the brain and it answers by sending a command to the crystalline lens in order to modify its shape and therefore, allowing the image to get to the retina, thus creating a clear image. This action happens automatically and the process is very fast; it is similar to the autofocus process of a picture camera, which focuses automatically on what it detects in the central framing of the viewfinder.
So, after the light passes through the gelatinous vitreous humor (9), it will reach the end of the route in the eye: the retina (10); in this point the image is clear (I will explain later which are the cases where the image is not clear and why).

But unlike a picture camera, the image does not just stay in the retina. This eye’s innermost nervous layer is the one responsible for converting the photons of the light that it receives into nervous signals that can be relayed to the brain; there it interprets them and gives them a right meaning. Therefore, the brain is the part responsible for “developing the film”, that is, interpreting it (knowing what the object is, what it means to us, what emotion causes, how to answer before it, and so on).

In order to achieve this transformation, the retina (10) is composed of five kinds of nervous cells, which collect all luminous information. They are not just responsible for making the image clear, but they also extract the basic information of the object about its color, its shape, its orientation, its movement, transmitting it to the brain. The human eye transmits visual data to the brain at about the same speed as two computers can share data.

These cells are placed in the retina in different layers, but as I do not want to make it very complicated, I am just going to point out three of them:

The light passes through all retina nervous layers to reach the outermost one: the one composed by photoreceptors (called rods and cones) (A); there the incoming light is reflected and passes through the retina again in the opposite direction, transforming this light into nervous impulses and transmitting the neurological information through different layers of nervous cells to reach the last one: ganglion cells (C); in this layer their thin axons bundle together in order to get out the eye and to the Optic Nerve (11) and send the impulses to the brain, thus starting, the VISUAL PATH.

There are two subtype of photoreceptors: rods and cones (A) distributed by the whole retina, where each one has a certain function and location.

- Neither of them exists in the point of the ganglion cells exit (Blind Spot -12-).

- Cone cells are found mainly in the central area of the retina, because they are the cells responsible for the details (the clarity, the shape and the color) of the object. This central area of the retina is where the eye “machine” leads the image of an object, in order to see it clear and with 20/20 of vision. This central area is the macula (14) (http://rosavisionenglish.blogspot.com/2008/05/little-bit-of-basic-ocular-anatomy-eye.html) and its central point with higher vision in the retina is the fovea (13) (http://rosavisionenglish.blogspot.com/2008/05/little-bit-of-basic-ocular-anatomy-eye.html). As these cells are the ones responsible to catch the details, they work better with well-light conditions. So, some activities where these cells are used are for instance, when reading or writing.

- Rod cells, in the other hand, are found mainly in the peripheral area. As we get away from the macula (14), the quantity of cones decreases and the quantity of rods increases. In the peripheral area the information about the clarity or the color is not so important, but detecting the orientation or the movement of the object that we look at. Therefore, these cells are stimulated with low-light conditions. Also, these cells are very sensitive to changes in contrast even at low-light level.

These photoreceptors (A) at the same time, stimulate certain ganglion cells (C); that is, each type of photoreceptor stimulates one type of ganglion cell, so each cell takes a certain information; both information elements travel parallelly to different areas of the brain, and once there, all information is mixed. The brain gives the meaning of the world surrounding us: where the object is, what it is, how big is, what color it is, how far it is,… It takes all information from the world and puts it together, in order to find similarities and differences, compare, discriminate and so on.

Consequently, in one hand, CONES (A) send information to PARVO ganglion cells (C), which take the information about the shape, the color and the detail, that is, what the object is; they help us identify and take out a meaning; help to see that object clearly (the Visual Acuity) and they work better if the object is stopped.

In the other hand, RODS (A) send information to MAGNO ganglion cells (C), which take information about the movement, the space and the orientation; that is, they report on the movement direction, its speed, calculate distances, where the object is, where I am and three-dimensionality. They help us move ourselves inside a dark room avoiding that we hit ourselves with other objects, or avoiding that we crash with the things that we do not look at directly (for example, with the doorframe when we go through it without looking at it), and so on.

As you can see, we do not just “see” the objects, or rather, we do not just see them clear or blurred; what a retina catches from an object, that image, is not only a picture, goes along with much more information and it all begins to be processed in the retina. But the rest of this complex but amazing processing of visual information that happens in the brain, will be explained it in the next post…

RELATED POSTS
A little bit of basic ocular anatomy… Eye or Ocular Globe
A little bit of basic ocular anatomy… What is the eye surrounded by?

A little bit of basic ocular anatomy… What is the eye surrounded by?

2008-06-08T22:56:00.001-07:00

Enlace a entrada en español.

As I wrote in the last post, in this one I am going to briefly explain those structures surrounding the eye; they are as important as the eye itself, because if any of them are not in perfect condition, the visual information can not be adequately processed.

LACRIMAL SYSTEM AND EYELIDS

EYELIDS protect the eye against any element that “wants” to get in. There is a reflex that cause that, when we simply touch the eyelashes, the eyelid closes. This is a “little inconvenience” when we want to position contact lenses onto the cornea (1) or simply when we need to put some drops on the eyes.
Also, they cover the eye when we sleep and, along with the pupil, control the quantity of light that gets into the eye.

If blinkings are not frequent (they are different in each people, but, the average frequency might be 1 blinking for every 5 seconds), the tear is not totally extended by all the cornea (1) and thus the cornea is not correctly lubricated, causing problems of clear vision, reddening and stinging of eye, discomfort with the contact lenses, and so on.
But all these problems are also caused, when the eyelids are not completely closed in each blink, that is, when we blink and the eyelids margins do not touch. Many people blink that way, and they do not know it. In fact, my eyelids blinked wrongly before I started my degree; one day, as I was doing my practice, one colleage let me know it.

People using computers in a frequent basis, usually suffer these problems and in general, everybody that work many hours doing tasks that involve looking at near distance. These people concentrate so much on their tasks, that they “forget” to blink. This paper shows an interesting guide about how to blink consciously the correct way so to automate it and thus to avoid present or future ocular problems.

The TEAR serves to protect the cornea, cleaning and moisturizing our eyes. The Lacrimal Glands (in upper eyelids) produce tears that flow over the cornea (1). The tears drain into two small openings at the inside corner of the upper and lower eyelids called the Lacrimal Puncta. The tears drain into the tear ducts (Canaliculus) and then into the Lacrimal Sac and finally into the back of your nose and throat (Nasolacrimal Duct). Now you can understand why when we cry, “we cry with our nose, too”.

If many tears are produced and they are not correctly drain (Epiphora), the tears will drain down the face rather than through the nasolacrimal system. It is the feeling that the eye is always watery, with many tears.
Sometimes an obstruction is present in any of these ducts owing to a infection, this causes an inflammation of Lacrimal Sac (Dacryocysititis). Some babies suffer this infection (20-30 percent) and some adults, mainly women, because of aging.

Besides the Lacrimal Gland, there are some sebaceous glands in the eyelids, that produce the lipid layer of the tear. If any of them gets blocked, it might cause the following disorders:

- Stye: It is a red lump in the eyelid margin, very painful. It is caused by an infection of the sebaceous glands at the base of the eyelashes, with more or less depth. If it is deep, its treatment is more difficult.
- Blepharitis: It is an inflammation and irritation of the margins of the eyelids, due to an allergic, infectious, seborrheic, irritable or mixed reason. It usually occurs in both eyes at the same time, and it is recurrent.
- Chalazion: It is a hard and painless inflammation of some little sebaceous glands in the eyelid margin. It usually disappears in a few months, but it sometimes remains, develops into a cyst and its size increases. When this occurs, it causes aesthetic problems and, what is worse, might compress the cornea and modify vision. If they are small, they usually just need a corticoids injection, but if they are big, sometimes a little surgery is required to extirpate them.

MUSCLES

In one hand, six EXTRAOCULAR MUSLES (EOM) are surrounding the eyeball and anchor it to the orbit. The extraocular muscles control eye movement and allow to lead them wherever we want (while reading, practicing sports, driving,…).

The Superior (2) (top) and Inferior (3) (bottom) Rectus Muscles control the eye’s vertical movement (up and down).
The Medial Rectus (4) and Lateral Rectus Muscles (5) control the eye’s lateral movement (from side to side).
The Superior Oblique (6) and Inferior Oblique Muscles (8) help rotate the eyes inward and outward in order to balance the sideways tilts of the head (they cause an opposite movement to eye).

All six of these extraocular muscles work together to move the eye. They coordinate so that the eyes are always aligned.

Any trauma in any orbit bone may cause a partial or total paralysis of any of these six muscles:
- If it is a partial paralysis we are before a Paresis or partial loss of movement owing to the weakness of one of them.
- If it is a total paralysis we are before a Paralysis or complete loss of the muscle function that causes restricted movement.
In any of these previous conditions, the eye movements in both eyes are not synchronous and thus cross-eyed or strabismus may appear and, consequently, double vision (but I will explain this later on).

In the other hand, we also have PALPEBRAE MUSCLES, which give eyes their shape and allow to open or close our eyes voluntary or involuntary manner.

If any of the muscles described is altered, it may cause the following conditions:
- The upper eyelid is dropped (Ptosis)
- When the previous condition happens or when there is a recession of the eyeball, the eyes seem smaller (Enophthalmos).
- Or, alternatively, when the eyes are more opened that what is usual or the eyeball bulges anteriorly out of the orbit, they seem bigger (Exophthalmos).
- The lower eyelid folds inward (Entropion), and this causes discomfort because the eyelashes rub against the cornea constantly (Trichiasis).
- Or, alternatively, the lower eyelid folds outward (Ectropion), drying the conjunctiva and the cornea, as the eye can not close totally (Lagophtalmos).

Well, my intention with this post is not for you learn these odd scientific concepts, but that these problems are familiar to you, and as with the previous post, if for whatever reason someone mentions these terms, you have where you can look them up to know what they talked about.

In the upsets of the palpebrae muscles I have preferred not to show directly the pictures just in case they are disgusting to any of you.

RELATED POSTS
A little bit of basic ocular anatomy… Eye or Ocular Globe
A little bit of basic ocular anatomy… The Retina.

A little bit of basic ocular anatomy… Eye or Ocular Globe

2008-05-23T15:05:00.001-07:00

Enlace a entrada en español.

Briefly I am going to explain to you how the eye is and everything surrounds it; really I would need several posts, but I think that the basic knowledge of this post and the two next ones, it will be sufficient to understand others.

A cross section of the eyeball:

(1) CORNEA: It is the outer and front part of the eye and where the contact lenses rest on (not on the iris (2) -where some contact lenses wearers think-, as you can see in the graphic), because of its curved surface. In humans, this structure has a refractive power of approximately plus 43 diopters.
Its transparency is its main feature and it is crucial that this layer keeps this way, since it would be a sign of a pathological upset. This layer does not have any blood vessels but has many nervous endings, that is why it is so sensitive; this is the reason why it is necessary a contact lenses adaptation process. The corneal sensitivity in each people is different and that is why some people feel contact lenses as a little eyelash into the eye, and however, others feel it as a stone, which hampers us from opening the eye.

(2) IRIS: It is the colour ring.

(3) PUPIL: It is the round hole in the center of the iris (2), through which light passes into the eye. Pupil controls the quantity of light that gets in; if much light gets into the eye (we are in a bright or sunny environment), pupil gets smaller (it contracts); and if little light gets into the eye (we are in night or in a dark environment), pupil gets bigger (it expands).

(4) AQUEOUS HUMOR: It is the transparent liquid that resides in the space between the cornea (1) and the iris (2). It is responsible for the value of the INTRAOCULAR PRESSURE (IOP), that is, the Eye Pressure, which, under abnormal values, can be one of element of risk to develop Glaucoma (although this one is not the only element that we have to considered in its diagnostic). The normal value range is around 21mmHg, but depends on many factors.
IOP varies during the day; when we wake up the value is higher, due to the pressure that our eyelids make over the cornea (1) during the sleep hours. The value normalizes during the day, until the night when the value increases again.
Therefore, a good control of IOP requires to assess it at around the same hour of the day and to use the same assessment instrument.

(5) CONJUNCTIVA: It is the outer part of the eye as well (it is a continuation of the cornea (1)). It is a viscous membrane that covers the outer part of the eyeball and the inner part of the eyelid in a continuous way; therefore, when one contact lens moves on the eye, it is impossible that it gets lost behind the eye (as many contact lenses wearers are afraid of).
It is a transparent layer, but it has blood vessels, besides nervous endings.
These blood vessels and this layer become inflamed when the eye becomes irritated (due to an eyelash or some dust that gets into the eye, or because of contact lenses, an allergy, an infection, and so on).

(6) SCLERA: It is a tough and white layer under the conjunctiva (5) (in the outer part of the eye) and it covers the almost all the eyeball from the cornea (1) until the Optic Nerve (11). When the eye becomes very irritated, you can see much better its inflamed blood vessels.

(7) CHOROID: It is the next opaque concentric layer under the sclera (6).

(8) LENS: It is the biconvex “lens” (you can see in the graphic how its outer and inner face are convex surfaces), flexible and transparent that we have inside the eye, directly behind the pupil. Owing to this flexibility the lens changes both surfaces curvatures constantly and thereby, the light, getting into the eye through the cornea (1), focuses on the retina (10); that is, this structure allows us to focus on objects in different distances due to these changes of curvature.
This is the part of the eye where the Cataract occurs, because the lens loses its transparency. In humans, this lens has a refractive power of approximately plus 18 diopters, which is why, when the damaged lens is removed, doctors put a new lens in the eye to replace it. Its refractive power can vary according to the patient refraction and his visual needs.

(9) VITREOUS HUMOR: It is a jelly-like and transparent liquid that fills a big part of the eye between the lens (8) and the retina (10). It allows to maintain the shape of the eye and absorbs any knock. This liquid is mainly made up of water. So, when it loses its transparency, it is necessary to extract it and to fill with salt solution; but this surgery involves many risks. This part is responsible for the “floaters” which are perceived in the visual field as spots or fibrous strands. We can see them mainly when we look at a plain background (as white walls, sky,…). Floaters are generally harmless, but the sudden onset of recurring floaters may signify a disease of the eye.

It is crucial that the four transparent surfaces of eye (cornea (1), aqueous humor (4), lens (8) and vitreous humor (9)), maintain the transparency, in order for the light not to find any obstacles in its way.

(10) RETINA: It is the last concentric layer under the choroid (7) and surrounding the vitreous humor (9). It is the most important and complex eye layer, because it is made up of six kinds of nervous cells and it is wherein the visual information that gets in the eye is received, and wherein the image is created and processed by the brain later on. Therefore, it is the first part of Visual Process.
But this layer deserves one blog post just for it.

(11) OPTIC NERVE: All axons of ganglionar cells at the retina (10) (the last layer of nervous cells of the retina) get out the eye setting up this nerve and taking all information received in the retina, through the visual path.

(12) BLIND SPOT: It is an area in the rear part of eyeball, and it is the orifice where the optic nerve (11) goes through the sclera (6), the choroid (7) and the retina (10). There is no vision in this orifice because there are not photoreceptor cells - the first cells with the responsibility of receiving the visual information that get into the eye-.
In order to see it, let us do a little demonstration: Close one eye (for example, the left one) and stare at one target. Then, put your forefinger over that target and move it slowly out (on the right in this case and on the left if you stare at with your left eye); keep on staring at that initial target and maintain the horizontal height. Doing this, one certain moment, the forefinger tip will disappear, and will come back if we keep on moving your finger out.
This little area without vision in the retina is named “blind spot” and it is what we named Physiological Scotoma in the space. But the brain manages to fill this spatial gap, basing on what we see in the surrounding areas.

(13) FOVEA: It is the point of highest vision of the retina (10), since it contains the largest concentration of cone cells in the eye and is responsible for Central Vision. In the example above, it is the point wherein we focus on what we want to stare, the target (with the exception of strabismic people or people with “lazy eye”).

(14) MACULA: It is a little area in the retina without blood vessels and that surrounds the fovea (13). We see the things that we want to see within this area and perceive all its details (e.g. reading); besides it is the area responsible for seeing the colours and the vision under well-light conditions as well.
The rest of the retina (peripheral retina) is responsible for the vision under low-light conditions or at night, and it is very helpful when we move in the space to avoid being hit with the surrounding objects that we do not see directly.

These are some of most important structures of eye, or at least the ones that you can hear more often, and some concepts that I am sure someone, some time, has told you or will tell you about them.
I hope that you have now a better idea what part of the eye they were or will be talking about.

In the next post, I will briefly write about all structures surrounding the ocular globe, which are also very important for a correct visual functioning.

RELATED POSTS
A little bit of basic ocular anatomy… What is the eye surrounded by?
A little bit of basic ocular anatomy… The Retina.

Free prescriptions!!!

2008-05-09T19:43:00.000-07:00

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As I wrote in my last post, in Spain, the optician’s shops that belong to the big optical chains and also many little optician’s shops, nowadays, do not still charge when they perform an eye refraction examination. These professionals of vision do not value their services, but what service are they going to charge? Would they charge a refraction test executed in 5 minutes? Would they charge for something that anyone who might have not studied the Optometry degree and who might learn easily because it can be done monotonously or can do it mechanically? That has no value. That is not testing the vision.

The worst of all is that with that, we ourselves have been spoiling to the patient for many years. Optician’s shops that do not already offer this limited service, suffer the consequences.

So when people come into the optician’s shop, they believe they have all the rights for asking for and demanding many “complements” when they buy just some glasses, many times they are on offer.

When they pick the glasses up, after:

having tested the patient’s eye vision (better or worse, let me skip that for now),
having been advised about what glasses fit them better,
having recommended one or another lens according the patient’s need,
having requested their lenses to the manufacturer,
having fitted and fixed the glasses,

the customer might pay just 55 euros or might have a 50 percent discount in some of the glasses and by all the time and work that involves that sale, that is, all of those services that are done free. But that is not all, the customer, believes that has all right to demand “added values”: a hard case, a soft dustcloth, a cord, a lenses cleaner, and absolutely, the prescription.

Within an optician’s shop many opticians do not charge for their services but just for the products they sell. When we study the degree, teachers do not teach us how to sell, but how to be Optometrists. However, many people complain because the glasses are very expensive.

Now that in many optician’s, the opticians are beginning to charge the prescriptions, many people are complaining about that, and they are surprised because “this was not done before”. Maybe the service and the knowledge has improved. When the people visit a medical doctor, they pay for that, don’t they? And even worse, don’t people pay whatever is required to go to the ophthalmologist office that might actually test their vision the same fast an ineffcient way that the optician’s that I talked about above? If you pay for this service, why should not you pay for the one offered by an optician, or optometrist one, whose work is more qualified and that is going to offer you much more quality time?

My web site

2008-05-05T04:51:00.000-07:00

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In order to have access to both blogs (in English and in Spanish), I have created one modest web site, where you will find a little introduction about Vision Therapy, my profile, reference to other related blogs,…

But better that keeping on reading, go take a look!

Where to go if we notice any alteration in the vision?

2008-04-21T11:32:00.000-07:00

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Optician’s Shops, Optometrist Offices, Ophthalmologist Offices.

From a point of sanitary view, and in Spain, an Optician-Optometrist can work in any of these places and his occupation in each one is different.

Besides these ones, he can work in ophthalmic lenses factories, contact lenses factories, workshops for fitting eyeglasses, physics laboratories, etc., but I will just write here about the sectors that might concern the reader, since they are the places that you may need access to.

In Spain, the term “Optometrist” did not exit in the past, and people just knew about two types of professionals: in one hand ophthalmologists who were and are the medical doctors and in the other, the opticians, who were those that sold the glasses.
But this has changed. Our functions have increased and though our degree does not allow to pursue Doctorates in Spain, our profession grows day by day and each one of us specializes in whatever we like or perform better. Just like any profession.

OPTICIAN'S (SHOP)

Some Opticians-Optometrists work in Optician’s. This group is the most plentiful one. But although, in the past our functions were basically the performance of eye exams and selling in an optician’s, nowadays things are changing (little by little, unfortunately).

According to the Spanish law, an Optician's is not a shop, but a health center. As such, the most important thing is the visual health of the people that come in. But unfortunately I have to admit that this is not always the actual aim. The big optical chains and many little optician's shops, as in any business, lead their aims to earn as much money as possible and obviously that is attained by selling eyeglasses, sunglasses, contact lenses, and so on. The correction “must be obtained quickly”, forgetting the quality of the service and the deontological code that every optician should have engraved in his forehead. In these optician's shops an optician can not “dally” about one person who tells him his “visual problem”. “Do you see or not? Do you see with this one? You need some eyeglasses, follow me to the point of sale”. So sad... They are just sales-oriented opticians.

Fortunately not all optician's work with this way, and the quality of service is much better. Maybe the patient will finish buying some glasses, but at least he will go to home convinced that the manner has been much better and more qualified, and that he has not been just a customer number, but the patient “Mr. Smith”.

Some optician's (very few) have even increased some services in the last decade. They are not just responsible for advising and selling some glasses or adjusting some contact lenses or fitting a pair of ophthalmic lenses in a frame that the patient chose. Their work is more specialized. The glasses are part of their work but it is not the ONLY job.
The visual evaluation is more specific to each problem and so is its treatment. This is the reason why many opticians are beginnnig to charge this service. Really this is our work and it is fair to charge for carrying it out. It is a qualified service, which as any other, has its price (but I will write about this subject in another post, possibly the next one). These optician's shops offer more treatments through contact lenses or eyeglasses and some of them even offer vision therapy.

Although nowadays in Spain, our 3 year “Opticians-Optometrist” degree is the only training available (in Spanish), there are many seniors opticians that do not have the knowledge of an Optometrist. In reality, there should be a differentiation between an commercial Optician (who will advice on the glasses or contact lenses-buying process and its maintenance, or fit /fix your glasses, and so on) and an Optometrist (who will be able to carry out all of these tasks but also, he will be able to offer you a more complete visual evaluation and more treatment options for different non-pathologic visual problems). In USA this difference is much more defined legally , since the studies are different, the each one’s responsibilities are different too, and although an optometrist can work as an optician, an optician can not act as an optometrist , since it is considered that he does not have enough knowledge.

OPHTHALMOLOGY OFFICES

The optometrist can work in two kinds of offices. In one hand, people can find optometrists working in an ophthalmologist office. Generally, these are offices in private refractive clinics. In them, optometrists help ophthalmologists in ALL optometric-related examinations which are necessary to perform to any patient who will undergo refractive surgery (myopia, astigmatism, and so on). Only recently have optometrists started to work so closely with ophthalmologists.

OPTOMETRY OFFICES

On the other hand, and for me it is the most important thing, optometrists can already set up our own optometry offices legally. We previously required an ophthalmologist to do it and therefore, it was considered as an ophthalmologist office.

Generally, in these offices there is not selling of glasses, and if so, the room for it is so small, that is almost symbolic.

In any offices, the “customer” does not exist, everybody is considered a “patient”.

If you want to receive a visual examination, you need to make an appointment (some optician’s shops do it too).

These visual examinations are complete and sometimes they require one or even two hours depending on the patient’s symptoms and visual problem (I will explain this examination more later on, in another post).

Usually, people, who go to an optometric office, do not arrive complaining because they can not see at distance and so they need some glasses to see better. They are usually people who come with a visual problem that goes beyond seeing or not seeing clearly:
- “I can not read for many hours because I get tired very fast.”
- “When I am working with the computer I have eyestrain, burning and itching eyes.”
- “Sometimes I see blurred or double.”
- “My child has difficulty for reading, he always loses the line and he reads very slowly.”
- “Is there any way to avoid my child’s increasing myopia?”
- “My child has performance problems at school.”
- “My child has lazy eye and he has been wearing a patch all last year and he has not gotten any improvement.”
- “It looks like my one-year-old baby has a squint in one eye, but we are not very sure.”
- “I have undergone a skull-encephalic trauma after a car crash and I have visual consequences.”
- “I have Multiple Sclerosis and since I started my medical treatment I have many visual upsets.”
- “I do not feel safe when I am driving.”
- “I feel sick when I am a car passenger but not when I am the one driving the car.”
- …

With many problems people have, they do not relate them to vision, and many times it is the base problem of everything. And when the visual problem is treated, rest of associated upsets, that they did not know that were related, disappear.

In that visual examination so comprehensive, we can find where the problem is and how to solve it.

For that, we have different treatments or solutions in the office:
- Some glasses for seeing better at distance or at near.
- Some glasses to performing better.
- Some glasses to avoid eye deviation.
- Some glasses to prevent the head from tilting…

As you can see, there are many options for using glasses and the first one is just one more.
It happens the same thing with the contact lenses, but I will explain later how we use each one of our work “instruments”.

Besides using glasses and contact lenses for helping in the treatment of a visual problem, many times patients need to know some little guideline in order to use their visual system in an optimal way, and therefore, to remove their upsets and prevent them for appearing again. For that, we resort to the Vision Therapy. It is a treatment that might need more or less time to automate all what the patient learns in the office and put it into practice daily.

Some offices also are specialized sport vision or low vision; in any of them, optometrists use specific visual tests and procedures of vision therapy.

THEREFORE, after reading all this, I guess it is a little bit more clear where you have to go depending on your visual problem, and the service and/or the manner that you would like to receive.

Who examines the Vision? Differences between Optometrists and Ophthalmologists.

2008-04-04T11:16:00.000-07:00

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The professionals responsible for evaluating everything related to Vision are the Ophtalmologists and the Optometrists.

Ophtalmologists and optometrists, in many parts of the world, have always had “difference of opinions”, as I guess there is between architects and quantity surveyors. The difference is that Optometry is not the technical career of Ophthalmology and the optometrists’ work does not depend on ophthalmologists’. They are independent careers, with different aims and fields of evaluation.

For many ophthalmologists, we, optometrists, are just those who sell the glasses that they prescribe to their patients after they test them, or who test when the medical doctors have a very long waiting-list (as in the Social Security in Spain). Surely, many of them have always considered us “their little sister” with inferiority of knowledge. And we have always considered them the “bad people”, because many of them do not respect our work.

Simply said, each one has different vision models, with different knowledge. Each one covers distinct vision areas; therefore we all should respect each other and should not work in areas that we do not know.

In just a few words, ophthalmologists evaluate the sanity of vision and we, optometrists, evaluate the functions of vision.

I explain:

Ophthalmologists

The Ophthalmologist, as a medical doctor, is specialized in checking whether the eyes and the visual path are sane. And if any disease exists, they can prescribe the drug that is in need or perform a surgery to achieve the best cure.

It is true that they can prescribe graduated glasses. But although I do not want to generalize, many of them spend the same time testing that the time that many of my colleagues do at the optician’s. That is, their only goal is checking with what correction the patient sees better, and do not worry about anything else; for example whether it will be comfortable every day, whether it will create other different upsets, whether it really covers the patient’s initial upset,…
It is true too, that there are some ophthalmologists who have a broader vision model, they respect there are other ways to analyze the vision more complete and that a simply pair of glasses is not always the cure against a problem of wrong vision or uncomfortable vision.

Optometrists

The optometrist receives little notions at the University about possible pathologies that the visual system can suffer. But we are light- years behind the knowledge that an ophthalmologist has on the matter.
After graduating, some optometrists attend some courses of specialization where they can learn more about these pathologies, but my opinion is that as much as they can learn in one year of specialization or attending small courses, ophthalmologists study ocular medicine for 4 years specializing in them. Their pathological knowledge easily overtakes us. This is their field and not ours.

So, an optometrist is not a medical doctor and thus, in Spain:
- He can not diagnose any pathology, although we can see it and we know that a patient has a cataract, for example, we can not tell it to him; we must simply send him to an ophthalmologist, with more or less rush depending on what we see. Many times the optician or the optometrist can be the first one detecting a problem like that, and we must know to detect it and send him to a qualified professional.
- He can not prescribe any medicine: Neither any eye drops nor anything that contains a drug. We can advise artificial teardrops, vitamins or homeopathic products.

- He can not use any medicine in his office, and with that I refer to pupil dilator. The medical doctor has all responsibility for it. Sometimes, if a child does not collaborate and we can not get him to read a test while we perform an objective test - which allows to obtain the exact correction of eyes-, and we need this piece of data, using the dilator eye drops can be the only way, in these cases, to achieve it (I will explain how this works later). Then, the patient should be refered to an ophthalmologist to obtain this piece of information. In some US states, optometrists, even without being medical doctors, can use pupil dilator in their offices.

All right, I have described what the optometrist is not educated for, or what he should or should not do in those situations. But now, let me define what our functions are.

The Optometrist’s field of action is different and broader. An optometrist can find a “machine” that physically is fine, but does not work well.

An optometrist is able to test a patient in objective and subjective ways. He is the most capable professional to do it. In Spain, while an ophthalmologist studies for 4 years (besides other four previous years of general medicine) about ocular and refractive pathologies and their medical treatments (drugs and surgeries), in those four years they study very little about the optometric side, basically learning to perform sight tests, in the simplest way. But optometrists study, in the three undergraduate years, the way for testing and treating a problem of wrong visual functioning with different options.
One sample of that Optometrists finish our degree more qualified in this field than Ophthalmologists, is the “Letter to Publisher” in the Spanish Society of Ophthalmologist journal, that Dr Colome Campos (ophthalmologist) published in 2005. “The optometry: A challenge for the ophthalmologist in 21st century” (in Spanish). In this letter, he explained that he designed a study evaluating and comparing the refraction knowledge between MIR Ophthalomologist and 3rd year Optic-Optometry students. For it, they had to answer 40 questions test, about Optometry, Binocular Vision and Contactology. Result: Any ophthalmologist appeared at the test. “Only one intern was very kind, my gratitude from here, of excusing because his chief of Internal Medicine
prohibited him the collaboration owing to the questionnaire was excessively difficult.” (Dr. Colomé Campos).

All opticians-optometrists leave the University with the same taught knowledge. But later, some of us, as those opticians that works in some optician’s, whose only goal is to sell as many glasses as possible, will make a visual test similar to the one made by an ophthalmologist, and his treatment will simply be to order some glasses or contact lenses “for seeing better” (in the next post I will explain the different models of work that there is within my profession). However, some of us have specialized and updated our knowledge year after year, we know better how vision works and how its functioning can change; that is why, we can find out from the patient’s symptoms, how the visual problem is affecting the person’s life, what parts of vision we should test to find the problem and the best treatment. Many, many, many times glasses are not the solution, or not as the solution that many people know. And the optometrist knows how to use glasses, contact lenses or prisms the best possible way for removing all patient’s symptoms and for giving him other options that can help him. Not only his loose vision.

In later posts, I will explain little by little, the treatments or solutions that an optometrist can offer and what the best is in each situation. One of these possible solutions is the Vision Therapy. This treatment is necessary when the upsets are not solved with some simple glasses, can be or:

- because a disruption has taken place in the patient’s visual system owing to some cause in his life. In one moment a change occurred (e.g due to work stress, a divorce, parent’s separation, …) and the person began to use his visual system in a different way, the incorrect one; he modified the base, creating a wrong one, from which he has developed his visual skills. But as it is not the right way, the symptoms and upsets come up after some time;
- or because the development bases (visual and motor) were not created right when he was a baby.

Well, maybe this is a little bit abstract, but when I describe in another post what the Vision Therapy consists of, you will surely understand it much better. For now, what I want you to understand is that in vision there are more problems besides seeing 20/20 and optometrists are the ones meant to solve those problems. When the “eyes” do not work very well, you do not perform well too. Not only we have to see right, but we have to process right what we see, and our visual system has to be able to answer and perform the optimum way in all situations. A specialized optometrist in Vision Therapy can re-educate the visual system in order for it to have right visual bases or to establish them from the beginning if the person has never had them (strabismus, lazy eye, retained reflexes, …). He can teach the patient to use his vision the optimum way for getting the greater quality and performance in his daily visual task.

Therefore, the optometrist has different options of alternative treatments before resorting surgery.

I hope that with all this explanation, now the function of each professional of vision is clearer.

Finally, I would like to make use of this post to expose a demand: a little bit of respect by both professions. Each one has a work to do, so, we must not neither diagnose or treat what we do not know, nor underestimate or undervalue the qualified work of the other professionals if we do not know the field that we criticize. As well as ophthalmologists master pathologies and we, optometrists just “know” them; we master visual functioning and they just “know” it.

What each one of us must to do is to work as well as we know, and if both sides collaborate together, the patient will be the most favoured.

What is the Optometry? History

2008-03-19T11:08:00.000-07:00

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Optometry is the science that studies how vision works and its mission is preventing, detecting and solving the non-pathological visual upsets that a patient may present.
From refractive upsets (myopia, astigmatism, hyperopia…), all the way up to functional upsets (wrong focusing, visual system under visual stress, double vision sometimes,…), up to upsets happened during the development and the visual learning, not related to the fact of seeing in a clear and stable way, but to receive, understand, identify, discriminate size, shape and color, calculate distances and speed of objects, wrong eye-hand coordination, memorize,… I mean, any upset that impedes the achievement of the maximum visual performance with the minimum fatigue.

But really, in Spain my degree is known as Optic-Optometry; that is why I must point out that it has two inter-related fields of action.
• One physics side related to the study of the light in the vision, the lenses, the instruments used in Low Vision (they are optic aids for those people that have usually undergone a pathology or surgery, which has sufficiently reduced the clarity of the vision; those aids improve a little bit the quality of life), the optic materials and instruments, the manufacture of ophthalmic lenses (for glasses) and contact lenses, and so on.
• And another side related to the one above (because of the lenses that we use to correct a myopia or astigmatism, or the prisms for the strabismus), is the health side and it belongs to the area known as “Science of Health” (not Medicine); personally, I feel more identified with this side. This part studies:
- In one hand, how the light gets into the eye (creating myopias, hyperopias and astigmatisms). It is the part most related to physics.
- In another hand, how each eye works separately and together (whether they see clear, they focus right, they fuse well, …) to allow an optimum visual performance.
- At the end, how that light that gets in across the eyes, as visual information along with all information around it (auditory, tactile, vestibular,…), is integrated and processed neurologically to allow a good learning and an optimum general performance.

In Spain, this degree, is a three years “bachelor’s degree” that covers the following areas of knowledge: anatomy, biology, neurology, pharmacology, pathology, physiology, ergonomics, etc.; areas that for many people are in second place before the great field of the Optics (physics, chemistry, mathematics, geometric optics, instrumental optics, physic optics, etc.). When you graduate, and in order to be allowed to work lawfully, you need to sign on the Optics-Optometrist National Association (Colegio Nacional de Ópticos-Optometristas –CNOO-) compulsorily.
But in each country the educational period, the professional functions and the rules to execute the profession are slightly different. This creates a problem when you want to work in a different country than yours, since each one has its own “conditions”.

An optician-optometrist can specialize in diverse fields: Clinic Optometry, Contact Lenses, Child Vision, Geriatric Vision, Low Vision, Vision Therapy, Sports Vision, Neuro-optometry, Optometric instruments and Physic Optics.

In one hand, the History of Optics is very extensive. The ancient optics notions are unknown, but in the remains of Egyptian tombs, pieces of metallic mirrors were found, that probably came in useful for deflecting the sun rays. The Optics history narrates the history of the lenses, the discovery of the laws of reflection and refraction, and the formation of the images. It is interesting to know how the first optics instruments, like the telescope and the microscope, were invented, since most of the later optics instruments are modifications of these ones. If you are interested, the history is quite well explained chronologically in this link.

In the other hand, the History of Clinic Optometry and Vision Therapy in Spain has evolved along with the years (quite slower than in the US):

- In the University, the old curriculum (until 1995), we learnt a classic vision model, where most causes of visual problems are attributed to the genetics and the only solution to these problems are glasses or contact lenses, and surgery. This approach is a “victim model”, in which the patient is victim of the genetic, development or age-related changes, among others.

- Before the change of the curriculum occurred, a functional model came up approximately in 1985, where it was not just important seeing 20/20, but also that other visual problems can exist and where the solutions for these problems increase; checking that the visual skills can be developed through the use of techniques related to the oculomotor control, the improvement of focusing and the increase of fusional range from both eyes in a sequential and incremental way. Vision Therapy begins to arise. This approach is a “modified victim model”: the patient is victim of stress at near.

- In the new millennium the vision begins to be related to the rest of senses, integrated as a whole. A behavioral model comes up, where many visual and perceptual problems are related to a poor motor and neurological development. The visual problem is not caused due to the stress at near, but because people respond to that stress. The therapy is much more individualized because it depends on the individual needs, skills and goals of each person. It is not a procedure for improving the vision, but the conscience and the person, making internal changes in the individual that creates the improvement. The approach is a “no-victim model”: The patient knows what he does wrong and can modify his behaviour consciously, in order to, through those internal changes, improve his visual and general performance.

This last vision model is not so novel in USA; it is being developed since 1970 and it is the model that I have come to study right to its birthplace.

What is VISION? Its importance.

2008-03-04T10:57:00.000-08:00

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As many people know, VISION is one of the five traditional senses. Nowadays, some people include in this group the balance and the proprioception too; I will calmly explain these terms later on.

Vision is the most important sense because up to 80 percent of the information that we receive, gets in across the eyes; not only the images but all the feelings that come with them too. That is why, it is very important that the visual system is effective, because it affects the learning and even the behaviour. In the reading case, up to 100 percent of the information that gets in, is purely visual.

People usually technically define VISION as “Action, effect and ability to see”. But personally, this definition does not satisfy me.

Vision does not occur only in the eyes. The eyes are just the most external part of a “complex mechanism”. They are the entrance. They are just responsible for receiving the object’s image; it is a very important function, but we do not see just because of them. Later on this image and all the information about it, follow a process until the brain is reached, and there we process, identify, understand, memorize, remember, learn and answer all the information that we receive. All that is VISION. Thereby, it is not only important that the image gets in but also knowing what to do with it. And that is what separates us from the animals; they receive an image that goes to the primitive brain but they do not learn from, memorize, understand, interpret it... The thinking part is what makes us different. And this is achieved by the NEOCORTEX (the “wrinkled dough of the brain”).

Thereby, in order for vision to be perfect, it is required for the COMPLETE visual path (not only the eyes) to be in perfect condition.

Vision is not efficient if:
- any of the eye’s layers prevent the light from getting in, that is, they lose their transparency;
- the light is not transmitted from neuron to neuron from the first layer of nervous cells which is inside the eye (which is known as the retina, the layer that receives the luminous stimulus), as far as the last neuron of the brain (in many areas of it, not only in the purely visual one);
- or there is some injury in any part of the visual path.

In another post I will explain the steps that occur in the Visual Process and that the vision does not just mean seeing 20/20.

It is crucial to have a good vision for the general development of a person’s life, and it is the most important tool for a child to have success at school. If the vision fails, the child’s school performance or the adult’s work performance fails too. Take one moment to think how many visual activities we do every day: at school or at work: reading, writing, drawing, painting, building, calculating, having contact with other people, fixing some things, cutting hair, putting bricks,… And during the rest of the day: when we take the right bus, drive, walk the street, eat, cook,…
Constantly, we are receiving visual information from which experiences are created. They can be better or worse depending on the quality of the information that we receive.

Nowadays, in Spain, the Optics-Optometrist National Association (Colegio Nacional de Ópticos-Optometristas –CNOO-) and in USA, the College of Optometrists in Vision Development (COVD) estimate that:
- up to 25 percent of the schoolchildren may have visual problems not diagnosed, that can affect their ability to learn (COVD) (CNOO)
- up to 70 percent of schoolchildren who have a learning disability in reading have some sort of visual problem; (COVD)
- and around 30 percent of school failure is related to visual upsets. (CNOO)

One child thinks everybody sees the same way as him; so, if he sees wrong, he will say nothing because he will think that it is usual. Therefore, the parents and teachers are the ones who have to suspect or recognize whether a child has some visual problem. The discovery and early treatment, before or during school-age, can avoid some future academic, emotional and social problems in the child. In future posts I will give a list of some signs and symptoms of visual problems that may indicate the need for a comprehensive vision exam, that I hope it serves you as an orientation.

When we are born, the vision is not a sense totally developed; so, everybody has to “learn to see”, just like we learn to walk. We have to learn to interpret the visual information that we receive. And just as the child’s motor development happens step by step while growing, the same happens with the vision. Both developments happen in parallel. So, if the child skips any motor development phase, it can affect the visual development, thus causing lazy eye, strabismus, or learning disabilities.

“We do not see with the eyes, but through the eyes” (Larry McDonald O.D.)

Who can be interested on my blog?.

2008-02-19T10:48:00.000-08:00

Enlace a entrada en español

As I said in the previous post, this blog is not for other optometrist colleagues who are specialized in the same area as me. It is for the rest of the people, a broad group of people worried about their own eyes or about other people’s eyes, and how the vision works.

Specifically, this blog can be interesting for:

- As I said, any person that, suffering visual upsets, has visited an optician’s or an ophthalmologist office and they have said she sees 100 percent and she does not have any visual problem; or in another case, they offered some glasses and following the “professional advice”, she thinks that it is the only solution. But she keeps on noticing she does not perform well in her job or in her studies; she can not concentrate many hours; it is difficult for her to change the focusing on different papers-computer over the table, or to do near-to-far and/or far-to-near fixation changes; the letters “dance” when she reads, her eyes get tired when she does it; she can not take many hours reading, sewing or doing handicrafts; she has headaches or eye stinging; she is not able to enjoy reading a book, in fact, she has never liked to do it, … a vast number of symptoms that some simple glasses or contact lenses, used to only improve the “quantity” of vision, are not enough to improve the “quality” of vision.

As we will see later, sometimes glasses can relieve that symptomatology, but it is not always enough. A specialized optometrist could offer more variety of options to relieve her upsets.

- Any father, mother, grandmother, uncle, friend, neighbour, nanny,… being in contact with a child and they want to make sure that the child has an efficient visual system that allows him to develop a good learning at school and to avoid any problems at sports, social contact with other children or adults, and so on.

In everyday life, parents, better than anybody, can observe whether their children are using some compensatory method of any visual problem that their parents do not know that their children have. For example: getting too closer to the TV; getting to closer the paper when they are drawing, writing or reading; rubbing their eyes a lot; tilting their head very much or even resting it in their arm when they do any homework at near, in order to use only one eye; avoiding any of that homework at near; missing the line when they read; needing the help of their finger to do it; reversing letters or numbers; changing the position of some letters within a word; being very sensitive to the light; etc. Everything indicates the existence of a visual problem, that discovered on time, it would not affect their learning or their general life.

- Any education professional, from nursery schools, all the way up to the elementary school and finishing in high school (teachers, assistant, nurse, psychologist, …)
Just as their parents, these professionals spend much time of the day in contact with children/teenagers. It is not the same case, because for each father his child is “his child” and teachers have many “children” to worry about. Many times the signs are too obvious; other times, not so much.
Fortunately, the concept “learning of disabilities” is better known and recognized each time. There is more and more information about this subject in many professions, not only in education.

Do not go so far, in my generation, if a child got bad grades at school, he was simply a bad student and he “did not want to” study or he “was not good” to study. Nowadays any professional looks at this subject in depth and looks for the cause why the child suffers from school failure. But fortunately you, education professionals, already know it. But, what I want to remind you is that most information that a child receives is visual, and almost all information that is not directly visual, is related to it. That’s why, it is very important that you always make sure that if a child “fails” at school, the cause is not related to any visual reason. Your observation along with those of their parents is crucial to detect these visual problems.
I do not believe in the concept that a child is “lazy” or that he is more “stupid” than the rest. Everybody had potential when we were born, and we “learn to see” with our experiences. The problem is that while some people have known or have had the opportunity to develop this ability, others have not.

Signs like these: not obtaining the main idea of a text or not knowing how to summarize; moving his head when the child is reading or doing it in a monotonous way; not remembering or understanding what he has read; being a restless child on the chair; winking his eyes, covering one of them; copying from his classmate’s notebook; being bad at sports; having bad handwriting… these and more are indications of masked visual and perceptive problems, which people do not think enough about. Providing a correct treatment, the child improves his school performance, improving his visual performance.

- Any another professional specializing in children: pediatricians, psychologists, pedagogues, speech therapists, neurologists, ophthalmologists, otorhinolaryngologists, occupational therapists, physiotherapist, osteopaths... Well, I am sure I forget someone, I am sorry. We, optometrists and visual therapists, belong to all that huge group of professionals that take care of the health of the child, each one from our own speciality.

The next fragment expresses what I think VERY WELL. This belongs to a post of Rosina Uriarte’s blog (in Spanish language) (specialist in Early Stimulation). She expresses the ten things she more “detests”. I just want to show the seventh one because it talks about what I am writing:

(Excuses, I have tried to translate it the best way I could :-))

“…I detest the war of rivalry among the professionals: "Don’t go to the optometrist office, they aren’t medical doctors”; “The psychologist doesn’t know anything about this…”; the neurologist, the psychologist, the speech therapist, the physiotherapist… Each one of them just looks at their own subject, they do not look beyond that, and parents have to put up the puzzle by joining all pieces… But the child is a whole, is not a pile of single pieces… THE MULTIDISCIPLINARITY IS VITAL TO TREAT ALL MANIFESTATIONS OF THE PROBLEM IN THE CHILD AND TO ATTAIN A SOLUTION. The child is a unit; it is not enough putting a patch here and other there…”

I think I would not have expressed it better. The child would be better treated if ALL OF US WOULD WORK TOGETHER, if all of us would know about other professionals’ existence too and if each one would work within our own specialty, without trampling on the work of other professionals.

I know that some parents think: “Well, so I have to visit many offices for my child to be fine and I do not have any time to do it. I have a job…” This is a thorny issue that only depends on the parents and what they want for their child. The perfect thing would be for parents that all these professionals were working in just one center, so the families would only visit one place; but unfortunately that does not exist. A good job is achieved, if each professional helps within his area the best way he knows, but is able to send him to another professional, thus helping the child as a whole. His problem would be solved sooner.

- Neurologists specializing in illness or traumatism which symptomatology or drugs necessary for the treatment, disturb the visual function (like Multiple Sclerosis or some brain injury, etc). In many of these cases, that visual function can be improved, and thus, at least we improve their quality of life a little bit.

- And not less important, any optician not specializing in this area who wants to know what the visual therapy is; how a neurological problem, development problem or learning disability affect the vision; knowing that there are more options besides conventional glasses or contact lenses; and sometimes, that those same options can be used to achieve another goal. And of course, the same as other professionals, they can send their patients to specialized colleagues, when the patient’s visual problems do not fall within their area.

Who am I?

2008-02-04T10:43:00.000-08:00

Enlace a entrada en español

I am a Spanish Optometrist since 1995. I specialized in Vision Therapy 2 years later. I attended other courses specializing more in Primitive Reflexes and visual neurology. I was working as Vision Therapist in Madrid until I went to California in 2007.
There I received more education in USA during 2007, with experts like Dr. Robert Sanet, trying to learn how optometrists work there.

(March 8th 2008: I received more continuing education about Vision Therapy and Neurology in USA, in different American Universities until 2008. In 2009 I stared a Behavioral Optometry and Vision Development Therapy office in Madrid, Spain).

I love what I do. I know we, the optometrists and vision therapists, have a hard struggle that people understand what we do and that Vision Therapy works. Many times I have been surprised by great improvements obtained in a patient. I understand why these improvements occur, but I am always surprised by everything related with the brain and its huge potential. So, I will explain the connection between the Brain and Nervous System with the Vision and Vision Therapy.

This blog is meant for people (patients, parents,...) to better understand how Optometry works and free it from the “Glasses or Sunglasses store” idea. Because Optometry is much more than that...

The reason why I write in Spanish and English language is only to reach more people.

Welcome to my blog!!

2008-02-04T10:39:00.000-08:00

Enlace a entrada en español

As the blog name indicates, the main subject is the Vision and everything related with it.
In this blog I am going to try to explain some concepts about vision, optometry, vision therapy and neurology related to all of this.

But this blog is not for experts on these subjects. It is for you… or for you… or for you too. It is for those people that have always wanted to know a little bit about their own eyes and how they work. Or simply those people have had a visual problem, have gone to visit a “professional of the eyes”, he has offered them as an only solution glasses or contact lenses, but really he has not solved their problem. Their inconvenience or difficulty to work, to study or basically to perform well, keep on existing.

I am going to explain how vision is not just a couple of eyes and how an efficient visual system does not depend neither on just having healthy eyes nor seeing 50 or 70 or 100 percent of vision. How a child who does not achieve good grades in the school, is not simply a lazy child who does not like reading or studying, nor he is a troubled child who does not like paying attention and also he disturbs the rest of children in his classroom. Behind all that, there can be a visual reason that upsets his perception and simply that child does not receive, process and answer the visual information from the environment the same way another child who apparently does not have any problem. I will explain that these cases can be treated and they can make the child perform much better in the school and even, enjoy reading and take a book because he wants to and not because it is mandatory.

I will start laying the bases: What is the Vision? Who tests it? Difference between optometrists and ophthalmologists. The Eye. The Visual Process. The Visual Therapy… As an entry door to other different visual problems, treatments and even some of my patients’ authorized personal opinions. I think this way everything will be much easier to understand.

I am going to explain everything in whatever easiest way possible. Therefore, do not wait for a “master class” or for a “very professional lecture” because that is not my intention, my real intention is to get your participation. If some of my entries leave you questioning, I will try to explain it again with simpler words, but I need your collaboration for this blog have the usefulness that I wish: to solve many “questions about the visual world”.

This blog will not come in useful for solving personal cases. At most, I will just give you an orientation in your questions. In order to find a better solution and a treatment of a visual problem, it must ALWAYS be examined from different points of view and, absolutely, the patient’s vision must be tested. Thereby, if in some moment, you recognize some symptoms in yourself or in your children, etc., my recommendation is that you should go visit an optometric and vision therapy office for it to give you the services in need.

I am also not going to write about ocular diseases or medicines, since I am not a medical doctor nor a physician, thus it is not my area.

So, … WELCOME TO MY BLOG!! :-)