Vision versus Eyesight: Vision Therapy
Vision versus Eyesight: Vision Therapy
Exactly what is vision? Is 20/20 vision adequate for reading ability?
In an article written several years ago by Dr. Donald J Getz, OD, FCOVD, FAAO, the terms vision and eyesight were defined rather differently, although many times they are used interchangeably.
Dr. Getz defined eyesight as “simply the ability to see something clearly,” as in an individual having 20/20 eyesight as measured in a routine vision examination, while he deemed vision as “the understanding of what is seen.” Seeing “20/20” means that the person being tested is able to see letters that are the same size and distance as those that most other people can see of the same size and at the same distance. In other words, if most people can see a line of print from 20 feet away, and the person being tested can also recognize printing of the same size from the same 20 feet he or she is said to have 20/20 vision.
Vision, on the other hand, implies the ability to not just recognize shapes and objects but to take that information and process it so that is has meaning.
Dr. Getz went on to make two broad, general statements about vision. The first is that vision is not innate, or inborn, but that it is a learned skill. The second is that this learned skill is often taken for granted by parents and others, because it is not as visible as other skills such as walking and talking. A child learning to walk and talk has the opportunity to imitate his parents and siblings to help him learn, and parents can observe that their child is developing these skills as expected; the development of visual skills is not as obvious and parents assume it is progressing normally, but they have no way of assessing that it is actually doing so.
Learning Visual Skills
If vision is learned, then vision is trainable. If a child does not gain the needed visual skills, they can be taught through vision therapy, sometimes called vision training techniques (VT).
Most western schools depend heavily on a child’s ability to use vision to learn, especially in learning to read. It has been estimated that about 75% to 90% of all learning is via vision, it is only common sense that if there is a lack of visual skills or any interference in those pathways, the child will not be able to integrate the information and will not be able to perform as well as might otherwise be expected.
In most western schools, children are learning to read in the early primary grades from one to three; after that, from fourth grade (age 9 or so) they begin to use their reading skills to learn. If their visual skills are lacking at that point, their academic performance will drop ever more steeply.
Visual Skills Needed for Academic Success
There are several visual skills needed to assure academic success in most schools, including:
- Visual acuity: Otherwise known as clarity, or sharpness of eyesight, this is usually expressed in terms of 20/20 eyesight. As noted above, this only means that the person can see as clearly from 20 feet as most others do; unfortunately what a child can see from 20 feet is not always applicable to how his vision functions close-up, where reading and learning usually take place.
While clarity is important, when a child is said to have “20/20 eyesight” parents and/or teachers assume that the child’s vision is normal and that any reading or learning problems are not vision-related. Actually, there are many other visual skills that are as important as, or even more important, in learning than visual acuity alone.
- Eye Coordination: This is one of the more important visual skills necessary for learning. We are all born with two eyes, but we must learn how to use them both together, as an integrated team. Most children learn to do this easily, but others can develop a problem known as exophoria, a tendency for the eyes to drift outwards. (It should be noted that this is not the same condition known as exotropia, where one eye may be seen to be aimed away from the object being seen. It is possible, however, for exophoria to progress to a type of exotropia known as intermittent, only occurring under certain circumstances, like when the person is tired or when reading.)
- Adequate Convergence: While reading, there is a demand for the two eyes to each turn inwards so that they are both aimed at the task. If the eyes tend to drift outwards, as in exophoria (above) the child must use extra effort and energy to keep the eyes aimed properly. Many studies have shown that the greater the effort needed to keep the eyes fixated properly, the less comprehension there will be.
When reading, the eyes do not move smoothly over a line of print, but they make a series of small fixations which move from word to word. When there is too much exophoria, each time fixation shifts from one word to another, the eyes drift outwards and each time they must be brought back into alignment again. When this happens over and over again, comprehension suffers; the common response to this is that reading becomes difficult. Sometimes, the child’s comprehension of the material can be so poor that he will find reading to be “boring,” simply because the lines of print don’t mean anything while he is reading them. The brain is too busy trying to align and re-align the eyes and has no extra energy available to gather meaning from the reading.
In addition to poor comprehension, when he makes the eye movements and must realign the eyes, his fixation may not be accurate, so he may omit words or lose his place easily. He may confuse small words, or add a word or two to try to make sense of what he reads. Children who have this type of problem may use a finger to help guide their eyes along a line of print; another symptom is that binocularity may break down and cause the child to see double.
Of course, if a child finds reading difficult or boring, he or she will avoid having to do it if it is possible to do so. A child will usually not complain about his ability to see or use his eyes, because he thinks everyone sees the same way he does and has no way of comparing his vision with that of anyone else.
Children who have this type of difficulty are at risk of being labeled as dyslexic or learning disabled, having a short attention span or to simply not be trying hard enough. Many times, very intelligent children who are trying very hard have even been termed as having minimal brain dysfunction or having ADHD.
- Too much convergence: Another type of eye coordination problem is called esophoria, which is the counterpart to exophoria (above), in that the eyes tend to turn too far inwards. When the eyes fixate at a point which is closer to their eyes than the actual target, there is a strong tendency to bring the object closer, but this only serves to make the eyes even more inwards. The result is a child who tries to read with his nose close to the page, but still not getting anywhere with reading the book.
- Astigmatism, hyperopia and myopia: These are termed refractive errors and are easily diagnosed and corrected with spectacle or contact lenses to provide clear and comfortable vision. The most difficult for parents to spot is hyperopia, or farsightedness, because farsightedness can be largely compensated for by extra focusing of the inner lens of the eye. The focusing and convergence systems of the eyes are linked together, so a child who has uncorrected farsightedness will usually see clearly, particularly in the distance, but will have too much convergence when reading. (see above)
- Eye-to-Hand Coordination or Visual-Motor Problems: Children who have poor hand-eye coordination tend to be clumsy, trip easily, and may have trouble with sports that involve catching or throwing a ball. These children are often observed using distorted postures while reading, using head tilting or covering one eye in an attempt to keep one eye covered or tilted away from reading.
- Binocular Reading: Often, children who have trouble using the eyes as a team will read very well if either eye is covered, but do not perform well when using both eyes. It is interesting that some children (and adults) read well when they are not trying to coordinate their eyes together; it is only those who have binocular vision but are not very good at using those binocular skills that have trouble with reading. In extreme cases of poor binocularity, the brain must choose between double vision or suppressing the central vision of one eye. Monocular vision will always win out over seeing double.
- Directionality: It is convention of our cultures that languages based originally in Europe such as English, French, Spanish, German or Italian, that we read from left to right. Other languages proceed from right to left or vertically. This is another visual skill that may be lacking in some individuals, but which can be learned.
- Form Perception: It seems incredible to many, but this important visual skill which can have a detrimental effect on learning and academic success is lacking in some children. When presented with a card printed with a shape, for example, a square, some children cannot copy it accurately, but will draw it in a distorted way. Some children cannot tell the difference between a square and a rectangle, or between a circle and an oval, for example.
It seems reasonable that if a child cannot interpret basic shapes, he or she will also have trouble perceiving the shapes of letters, which in turn make up words, which make up sentences which stand for abstract ideas. Form perception can also be learned.
- Span of Perception: Children just learning to read will often see only one letter or one word at a time, but reading speed and comprehension can improve dramatically if the child can be taught to perceive three or more words at a time. An easy way to visualize this is to imagine reading through a straw; the larger the span of perception, the easier and faster it is to read.
- Visualization: In the example cited just above, the reader was asked to imagine reading through a straw; if the reader is able to do so, he or she must possess what is widely held to be the ultimate visual skill, that of the ability to take specifics and apply them to abstract ideas. The ability to visualize deeply is also a trainable skill.
All of these skills are possible to learn with the proper VT exercises, which most children find interesting and fun. With so much depending on academic success for future opportunities, it seems reasonable to invest some time to make learning and reading so much easier and efficient.
Nutrition and Vision
When a child has difficulty learning, it is usually a problem with more than once source; often the underlying cause is nutritional. One of the most important things parents can teach their children is to eat properly, with a wide variety of foods supplying a wide variety of nutrients. If a child has sugar-frosted flakes with chocolate milk for breakfast, a candy bar and a soda for lunch, and pizza for dinner, their nutritional needs are obviously not being met, especially if this description holds true for most days.
The occasional sweet or soda isn’t going to harm anyone, but relying on them or other processed foods for a major source of calories and nutrition is not adequate to provide for a day’s activity and learning. In short, what the body needs, the eyes also need.
A diet of high quality nutrition-rich foods that are not processed is important if the child is to be successful in academics or learning the visual skills needed.
Vision Really is a Learned Skill
Reading, whether it is from a printed page or a computer screen or electronic tablet, is a skill many of us take for granted. When it is easy and efficient, we use reading to take us to new places and different ideas; when it is difficult, an entire source of knowledge can be closed.
Some tips for parents whose children do like to read:
- Make sure the child has a good place to read, where the light is good, and where the book can be held comfortably at the right distance from the eyes, about 15 inches or so.
- Do not allow children to read while lying on the rug, because the book will be too close.
- Encourage reading by making books and magazines readily available; visit the library often and allow the child to choose what books he likes.
- Reading should be fun, not a chore; not everything should be “assigned.” Allow and encourage reading for pleasure.
Vision Therapy exercises (VT) has been shown over the last fifty years to be of great value in improving school performance and reading. It has been shown time after time to have a positive effect on the ability to learn.
Experts in education and learning disabilities and dyslexia can be quick to discount the effects of poor visual skills on reading, and while it is certainly true that these conditions do exist independent of vision or visual functioning, parents should be aware that once such a label has been placed in a child’s school records, it will follow him throughout the course of his scholastic career, and may even have implications for opportunities or choices that may, or may not, be available to him in the future. The problem is that most of these experts are talking about eyesight, not vision.
At the very least, children who are having trouble in school with reading difficulties should have a vision examination with a qualified optometrist as a first step to finding a solution.
Before the age of three, each child should have a vision examination, and again before beginning either kindergarten or first grade, if for no other reason than to rule out any uncorrected refractive errors such as astigmatism, hyperopia (farsightedness) or myopia (nearsightedness). Thereafter, because vision can change quickly in growing children, a vision exam is recommended each year, or at the first sign of any difficulty in school.
Vision Therapy is also indicated for children with any type of strabismus (eye turn) or amblyopia, a condition in which vision may not develop correctly or fully.