There is a lot of confusion about dyslexia and eye problems. Dyslexia is NOT an eye issue. Most children with dyslexia have completely normal vision. Some do have a problem with letter reversals, particularly at younger ages, but that is due to directional confusion rather than eye issues. (See Dyslexics and Letter Reversals.) Most of these students can be taught not to reverse letters with some simple techniques.
However, some people may have an eye issue which is known by several names such as: Visual Stress, Scotopic Sensitivity, Asfedia, or Irlen Syndrome. Irlen Syndrome is thought to be related to the interaction of the central nervous system and the eyes at a physiological level with light. For example, a person may say that the text seems to jump around on a page. A person with visual problems may be misdiagnosed as dyslexic because of a vision problem that makes reading difficult. It is also possible that someone with dyslexia may suffer from visual issues in addition to dyslexia.
It is important to note that there is great disagreement about the existence of Irlen Syndrome and its treatment. Researchers say that there are other known eye problems that case these problems, not a separate syndrome. They worry that people are spending money on highly advertised solutions like colored lenses and overlays without being evaluated and treated for appropriate underlying causes. In 2004, the American Optometric Association released the following statement:
There is evidence that the underlying symptoms associated with the Irlen Syndrome are related to identifiable vision anomalies, e.g., accommodative, binocular, and ocular motor dysfunctions, in many patients seeking help from colored lenses. Furthermore, such conditions return to normal function when appropriately treated with lenses, prisms, or vision therapy. When patients exhibiting the Irlen Syndrome were treated with vision therapy, their symptoms were relieved. These patients were no longer classified as exhibiting this syndrome, and therefore did not demonstrate a need for the colored overlays or tinted lenses.
On the other hand, many people feel that colored lenses and overlays are very helpful. Placebo effect? A lot more research needs to be done. It certainly will not hurt to use colored paper and colored overlays. In fact I try to print student work on blue paper just in case there is an undiagnosed eye problem. It may even be useful to use overlays while undergoing treatment if you find it cuts down on eye strain. I would stop short of investing in colored glasses without first visiting a qualified ophthalmologist. An ophthalmologist is a medical doctor. Please do not substitute a visit to the optometrist at your local glasses store!