A new study provided evidence that eyesight problems do not increase one's risk of developing dyslexia.

Dyslexia is the most common cause of reading, writing and spelling difficulties. About 70 to 80 percent of those with poor reading skills are believed to be dyslexic. The condition affects one in five students.

Doctors who diagnose children as dyslexic often offer eye treatments and recommend routine eye checkups believing that eyeglasses might correct the problem. But a new study of researchers at the University of Bristol in U.K. suggests that such procedures are unnecessary because the children do not have eyesight problems and that dyslexia might be caused by something else.

The researchers looked at the eye test results of 5,822 children ages 7 to 9. About 3 percent or 172 children were diagnosed with severe dyslexia, while 8 percent or 479 had moderate dyslexia. The results were compared to the eye test results of those with no dyslexia.

The analysis showed that 84 percent of the dyslexic children had perfect vision. Only 16 percent had eye problems, compared to 11 percent of those with no dyslexia. The researchers do not consider the difference as statistically different and concluded that dyslexia is not caused by eyesight problems.

"Some practitioners feel that vision impairments may be associated with dyslexia and should be treated. However, our study results show that the majority of dyslexic children have entirely normal vision on the tests we used," Cathy Williams, study lead author and a pediatric ophthalmologist, said in a university news release.

"So, families now might want to ask: what visual impairment is actually being treated, how it is measured and what is the evidence that treating it will help a child with dyslexia? This will help them decide whether any sight treatment offered is likely to help their child's dyslexia."

The researchers clarified that their study focus on providing evidence that dyslexia is not linked to eyesight problems, instead of looking for other possible causes.

The study was published in the May 25 issue of Pediatrics.