UNIVERSAL CITY, Calif. -- Colored plastic overlays -- particularly blue and gray -- used on books can produce immediate and dramatic effects on reading performance of children who are specifically-reading-disabled or dyslexic, says a University of New Orleans researcher.
"About 70 percent of the disabled readers we encounter have specific visual defects and about 80 percent of this group respond to this simple and inexpensive intervention," said Mary C. Williams, who holds a doctorate in psychology and specializes in the study of visual factors contributing to reading disability.
Specifically-reading disability, or dyslexia, affects an estimated 10 to 15 percent of the general population -- between 20 million to 30 million Americans, she told vision researchers and science writers at a seminar here sponsored by the New York-based Research to Prevent Blindness.
"We found we could simply reduce the contrast effects of materials or simply use color overlays -- at practically no expense -- and still get measureable effects," said Williams.
"The effect of this reading intervention is documented and it should be used only for reading at this point," she said.
Williams further cautioned that there are individual differences in effects of different colors, "so each child should be tested individually."
Concern was voiced by Williams and other researchers at the seminar that her work might be confused with the Irlen lenses, which have been widely used in this country and Australia in the treatment of learning disability.
"This product was marketed by Helen Irlen, a California psychologist, when there was no data to support the efficacy of colored eyeglasses for this purpose," said Williams. "There are still no data that support the efficacy of this intervention introduced in 1983."
She further said a recent study conducted by Dr. William Lovegrove near Sydney, Australia, showed no beneficial effect of wearing colored lenses.
"I think this is primarily because the lenses are assigned on the basis of client preference rather than objective measures," she said.
She said that children don't like to wear these colored lenses and she thinks wearing them "serves to further stigmatize this group."
Until recently, evidence of the presence of visual deficits in reading disability have been ambiguous and misleading and intervention programs aimed at building visual perceptual skills have proven to be ineffective. As a result, many current intervention programs concentrate on remediation of language skills.
Some researchers, including Williams, believe there is a dual processing system, and each system is separate but interdependent. If something goes wrong with either system, the reader will have problems.
The transient system transmits information about things that are moving and changing. The spatial system transmits information about fine details that are stationary.
"The systems have been identified at every site along the visual pathway up to the vision center of the brain," she said. "There is 20 years of psycho-physiology research behind this system."
Children who participated in a newly completed study at the university-based summer reading clinic she directs, did best when they used blue or gray overlays, although some showed gains when green or red overlays were used. Even normal readers did better with the plastic overlays.
A total of 70 children -- 32 normal readers and 37 with dyslexia -- were studied. The children were between 8 and 12 years old and had tested normal for intelligence, color vision, visual acuity, auditory problems and language ability.
Normal readers scored at above grade level on a standardized reading tests and the average reading lag of the dyslexic group was 2.2 years. Normal and dyslexic groups were matched for age and IQ.
Williams said she has submitted her findings for publication in a scientific journal, but the first phase of the color study will appear as a chapter in a book, "Applications of Parallel Processing in Vision," due to come out in November.
Williams said she plans larger studies of children to further document her findings.