Depending on the definition used, as many as one in five school-aged children in the United States may have dyslexia, the researchers said. If severe reading difficulties associated with dyslexia aren't addressed, they can affect adult employment and even health, they added.
The new findings, published online May 25, will appear in the June issue of the journal Pediatrics. The researchers tested over 5,800 children, aged 7 to 9, for a variety of vision problems, including lazy eye, nearsightedness, farsightedness, seeing double and focusing difficulties. The 3 percent (n=174 children) of children with dyslexia who had severe difficulty reading showed little differences in their vision than children without dyslexia. And 80 percent of children with dyslexia had fully normal vision and eye function in all the tests, the findings showed. A slightly higher proportion of those with dyslexia had problems with depth perception or seeing double, but there was no evidence that this was related to their reading disability. After making adjustments for other contributing factors, this finding seemed due to chance.
That research showed that the cause of the disability has to do with how someone processes letters and sounds, not with how they perceive letters and words in the first place, said Fierson. He is co-author of the American Academy of Pediatrics' policy statement on learning disabilities, including dyslexia. An initial eye evaluation to find out if eye problems are present is important, he said. But this is only to rule out problems or treat specific conditions -- prescribing glasses or contacts for nearsightedness or farsightedness, for instance.
"To date, the best techniques for the remediation of dyslexia involve intensive one-on-one -- or at least small group -- teaching by phonetic methods by experienced teachers," Fierson said. "At least as important, however, is an initial evaluation by a neuropsychologist or educational psychologist to determine the specific problem areas present in the poor reader," Fierson added. "Parents should avoid unproven quick fixes and go for intensive phonics," Fierson said. "As is usually the case, things that seem too good to be true usually are. This includes vision treatments for dyslexia."
SOURCES: Walter Fierson, M.D., pediatric ophthalmologist, Arcadia, Calif., former chairman, ophthalmology section, American Academy of Pediatrics, and co-author, AAP Policy Statement and Technical Report on Learning Disabilities; Mark Fromer, M.D., ophthalmologist, Lenox Hill Hospital, New York City, and director of eye surgery, N.Y. Rangers; Cathy Williams, M.B.B.S., Ph.D., senior lecturer, child visual development, University of Bristol, England; June 2015, Pediatrics