Wednesday, October 29, 2008

A good vision is not only seeing 20/20

Enlace a entrada en español

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"


Anonymous said...

Dear Rosa Garcia
Your blog about eye is truly helpful for me, i am Sanal from INDIA . I am studying for Bsc Optometry over here. the information you provided was helpful. i understand you are an optometrist ,i need your knowledge about optometry is unsatisfactory,i like to have your e-mail address.. thank you

Anonymous said...

Everyday we take our eyesight for granted and as this article points out; our eyes are one of our most treasured gifts and it is extremely important for us to receive regular eye exams and not wait until there is a problem. Our company Precision Vision ( is a world leader in developing testing devices and has paved the way with setting the standards that Ophthalmologist, Optometrists, and Opticians use to test your eyes. We are proud to be an instrumental partner with pharmaceutical and researchers around the world. We have a lot of information and eye charts that aide in diagnosis of Glaucoma and many other diseases that can be found on our website and welcome eye care professionals to review our Visual Acuity Measurement Guide posted on our website. Thank you.

Rosa M. García Hdez said...

Hi Laura,
I appreciate your information, but if you have read other posts in my blog, you will know that my goal is writing to parents, teachers or other professionals related to the children care. Information that you give is very interesting for me or other colleagues, but, I think it is not specifically useful for them. I have decided to publish your comment only in order to let the people know that I would not like to publish another comment with clear advertising objectives, mainly if I consider that the information is not helpful for my readers. I hope, you understand me.