Wednesday, March 19, 2008

What is the Optometry? History

Enlace a entrada en español

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.

Tuesday, March 04, 2008

What is VISION? Its importance.

Enlace a entrada en español

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.)