Researchers have been searching for causes for dyslexia for years now, but a new study out of England has found that it is not connected to bad eyesight.  Patients that had near perfect vision were diagnosed with dyslexia at the same rates as those who did not.

Researchers viewed the eye tests for 5,822 children between the ages of 7 and 9, comparing the results from 172 severely dyslexic children to 5,650 children who were either mildly dyslexic or not dyslexic at all, and found no large deviation between the two groups.

In fact, researchers learned that most dyslexic children actually had perfect vision based on the tests.  Results from tests for 3D vision and image fusing, the process of combining images from both eyes into one visual image, were also nearly identical between children with dyslexia and those without. 

This new study is the first of its kind to consider data from such a large number of people.

"Our findings may reassure families that their child's sight is very unlikely to be affecting their reading ability (assuming the need for glasses has been ruled out) and so they can pursue other options for supporting their child," said Dr. Alexandra Creavin, a research fellow in ophthalmic epidemiology and pediatric ophthalmology at the University of Bristol, in a press release.

"Fortunately there are treatments and training programs to help children with dyslexia that do have a good evidence base, including training in phonics (speech sounds)."

Dyslexia, otherwise known as reading disorder or alexia, is a learning disability characterized by trouble reading despite normal intelligence. 

It is estimated that one in five students, or 15 percent to 20 percent of the population has a language based learning disability of some type, with dyslexia being the most common form of disability.  Dyslexia doesn't discriminate, affecting the same percentage of males and females have dyslexia and it affects the same percentage of people from different ethnic and socioeconomic backgrounds.

Treatment for the disability usually involves adjusting the teaching methods to meet the individual's needs.  This does not cure the underlying problem, but it does alleviate many of the difficulties faced by people with the disorder.

The cause of dyslexia is believed to involve both genetic and environmental factors, although the true cause is not yet known.  This latest study, published in the Journal of the American Academy of Pediatrics, has now demonstrated that vision problems do not appear to be an underlying factor for this disability.