It almost sounds too good to be true. By placing a couple of tinted plastic filters over the page he's reading, Eric Johnson, a 25-year-old dyslexic, can double his reading speed. Words that were once fuzzy now snap into focus. Halos that once shadowed the letters disappear.
"I'm able to concentrate longer on the words, read faster and for a longer period of time," said Mr. Johnson, an undergraduate at the University of Maryland at College Park. Without the three 8 1/2 -inch-by-11-inch overlays, Mr. Johnson can focus on only a few words at a time.
Mr. Johnson's experiences would come as no surprise to Helen Irlen. A Long Beach, Calif., psychologist, Mrs. Irlen has promoted the use of tinted filters and lenses for dyslexics since the early 1980s. But her techniques have been regarded with suspicion, largely because some researchers and doctors could see no scientific basis for them.
Now, however, new research showing that dyslexics have a defect in the brain's visual system is focusing increased attention on Mrs. Irlen's methods. Yet people in the field of dyslexia continue to question the effectiveness of the lenses, as well as their high cost.
At the heart of the debate is a recent study in which a team of Harvard Medical School brain researchers reported that certain visual systems of dyslexics are more sluggish in processing stimuli than those of non-dyslexics. They also discovered that the cell bodies making up those systems are smaller in dyslexics than in those without the disorder.
Dyslexia, which is thought to affect some 12 million Americans, is typically associated with symptoms such as poor spelling, great difficulty learning to read and reversal of symbols in reading, writing and math. The disorder has nothing to do with intelligence.
Traditionally, dyslexia was seen as a malfunction in the way people understand language, without a visual component, according to Dr. Albert M. Galaburda, a Harvard University neurologist who took part in the study. But both this study, described in the Sept. 15 issue of the scientific journal Proceedings of the National Academy of Sciences and recent research on the auditory systems of dyslexics by Dr. Paula Tallal, a professor at the Rutgers Center for Molecular and Behavioral Neurosciences, points to the theory that dyslexics have several brain defects that hamper their sight.
"This research confirms a lot of our findings," said Ms. Irlen, whose 52 clinics around the world have prescribed tinted lenses for approximately 20,000 people, at the cost of about $400 a pop. "People didn't understand why [the lenses] worked, but this shows why you need to filter the speed or frequency of light."
According to Dr. Bruno Breitmeyer, a professor of psychology at the University of Houston who has conducted extensive research on dyslexia, timing of the visual systems plays an important role in a person's ability to read without words blurring, fusing or jumping off a page -- a frequent complaint of dyslexics. The Harvard study indicates that dyslexics' systems operate with a different timing than those of non-dyslexics.
Mrs. Irlen, who first outfits clients with a set of plastic overlays, then with the colored lenses, has claimed that one-third of those who use the lenses are left with no symptoms of dyslexia. She also says that the lenses work by combating scotopic sensitivity syndrome, a sensitivity to certain wavelengths of light which is thought to be common among dyslexics.
But many who work in the field of dyslexia caution against leaping to conclusions about the lenses.
Much of the skepticism centers around the preliminary nature of the study performed by the Harvard researchers -- only 10 living people were tested and only 10 brains examined -- as well as the lack of research available on use of the lenses.
"Our position is simply that we are concerned that when a study that deals with a very small handful of people, people are going to make a leap of faith to say that [the lenses] are the answer," said Rosemary Bowler, executive director of the Orton Dyslexia Society, a national organization that is headquartered in
Baltimore. "The jury is still out on the effectiveness of these kinds of treatments."
Ms. Bowler did not completely reject use of the lenses, however. "Anything that's going to make people more comfortable, easier for them to function, is certainly worth exploring," she said. But, she added, the necessity of using other approaches to treat dyslexia still exists. "The implication is that if you go out and spend $400, $500, $600 [on lenses], something magical is going to happen. It may help you. But it won't obviate the need for some very long-term, sometimes not terribly exciting educational intervention."
The traditional technique of educating dyslexics is a multisensory approach in which they learn to read by seeing words, hearing them and tracing letters with their fingers -- rather than just by sight.