This is the second in a two-part guest post by Dr. William O. Young. To read the first part, click here.
This is another twist on the tinted lens/overlay theme, though ChromaGen stresses that their lenses, which are various shades of gray and which may be different shades for the two eyes, are not the same as Irlen lenses/filters. ChromaGen lenses were developed 25 years ago as an attempt to treat colorblindness. More recently interest has developed in their use with struggling readers, and as was the case with Irlen lenses, the media have helped spread the word, including a very favorable (and uncritical) piece on ABC News: “Color-Filtering Lenses: Better Reading for Dyslexics?” November 30, 2011. (For a more objective review, see “The Healthy Skeptic: Promise of ChromaGen lenses for dyslexia a bit blurry,” in Los Angeles Times, November 28, 2011.)
Like the Irlen Institute, ChromaGen claims that their lenses help dyslexia by treating visual distortions, by altering the wavelength of light reaching the eye, and that about half of dyslexics could benefit from these tinted lenses (www.ireadbetternow.com).
Optometrists become ChromaGen certified providers by taking one hour (!) of online training and paying $1500 for a kit of lenses. After a $150 screening exam, a pair of ChromaGen lenses cost the patient $750 to $1200; ChromaGen tinted contact lenses are somewhat less expensive.
No one other than the inventor of the lenses, who obviously has a financial interest in the outcome, has published a study supporting their effectiveness for reading disorders. Nevertheless, just as there are people who swear by VT and Irlen lenses, there are people who feel ChromaGen lenses have helped them, and who have provided glowing testimonials. It is these testimonials that have driven ChromaGen sales, despite the lack of objective evidence that they work. The ABC story reports, “With such testimonials, ChromaGen’s Edwards downplayed the need for scientific studies to establish the lenses’ effectiveness.” Enough said. The placebo effect is a powerful thing.
These are very weak reading glasses prescribed by optometrists for struggling readers on the basis that focusing on reading material, at a reading distance, causes “near point stress” which is relieved by the reading glasses, thus allowing the child to read better. This concept of near-point stress has been a part of optometric training since the 1920s, again without valid objective evidence.
There’s no way to explain why this therapy is bogus without some numbers. When we focus on things “at near” we have to accommodate, meaning crank in focusing power, to make things up-close clear. (When we turn 40 we can no longer accommodate enough to see clearly at reading distance, so we need reading glasses.) Glasses prescriptions and accommodation are both measured in units called diopters. Assuming we are not farsighted, we don’t have to accommodate at all to see things very far away, but to see things up close (at book-reading distance) we have to accommodate about 3 diopters. If a child is, say, 1 diopter farsighted to begin with, she has to accommodate 3 + 1 = 4 diopters at near. But a child at, say, age 10 is able to accommodate about 14 diopters and can sustain half of that accommodation (about 7 diopters). This means that this child is not even breaking a sweat to accommodate the 4 diopters needed to see at near: she has 14 – 4 = 10 diopters in reserve that she’s not even using!
And how much help do these low-plus readers provide? 0.5 diopters, typically (though I’ve seen them even weaker)! So the farsighted child reading with 0.5 diopter readers only has to accommodate 3.5 diopters at near, instead of the 4 diopters she requires without the readers—meaning that with readers she has 10.5 diopters in reserve, instead of the 10 she has in reserve without the readers. This is a truly insignificant difference, and again, any “effect” is a placebo effect.
(Note, by the way, that these children who supposedly can’t read because of near point stress are able to play video games—without their “reading glasses”—for long periods at a time without difficulty…)
Omega 3 fatty acids are advocated by John Stein, one of the major proponents of the “magnocellular theory,” for treating reading problems (along with yellow and blue lenses). The magnocellular theory proposes that a certain type of cell in the retina of the eye fails to suppress the image of the letters you’re looking at now when you shift fixation to the next set of letters as you read so that a “visual trace” of the last group interferes with the group of letters you’re trying to read now. A magnocellular deficit is believed by some proponents of Irlen lenses and ChromaGen lenses to be the reason for their lenses’ “effectiveness.”
The evidence for the magnocellular theory is debatable at best; my best interpretation of the current evidence is that even if some people do have a magnocellular deficit—a big “if”—it is unrelated to any reading difficulty they may have. (See “Visual Search Deficits are Independent of Magnocellular Deficits in Dyslexia” in Annals of Dyslexia.)
And as for the omega 3 fatty acids, the evidence for their effectiveness in dyslexia is….? (I’m not aware of any.) Look, omega 3 fatty acids are great: I take them myself because there’s evidence of cardiovascular benefit, and I recommend them to my patients with blocked oil glands in the eyelids (a common problem that causes red bumps in the eyelids called chalazia). They cause no harm that I’m aware of, they’re relatively inexpensive, and unlike the remedies discussed above, they may actually do some good (though not specifically for dyslexia). So if I had to pick one dyslexia “remedy” from this list of five, I’d pick omega 3 fatty acids, hands down!
Here’s the bottom line.
It seems very reasonable and logical to think that the eyes cause or contribute to dyslexia. It’s reasonable, logical, and almost always wrong! Dyslexia is a language processing problem, not a vision problem, and the valid remedy for dyslexia is targeted language therapy with daily practice, not eye exercises, tinted lenses, or reading glasses. There is simply no valid vision-based shortcut to treating dyslexia.
We are all, myself included, susceptible to being persuaded by anecdotal evidence: our friend down the street says something helped their child, so (we think) maybe it’ll help ours! As a parent, you are motivated by your desperate desire to help your struggling child, whatever it costs.
I urge you to hold out for objective evidence from an impartial source and instead put your money toward valid language-based therapy that will actually help your struggling reader. Unfortunately, there simply is no quick fix for dyslexia.
For a comprehensive overview of the subject of the role of the eyes in reading and learning disorders, please see Learning Disabilities, Dyslexia, and Vision: a joint policy statement by the American Academy of Pediatrics, the American Academy of Ophthalmology, and the American Association for Pediatric Ophthalmology and Strabismus. It’s 32 pages and will take you a while, but is well worth the time.
For another objective review of controversial vision-oriented therapies for dyslexia, see the excellent article in the Winter 2011 edition of the International Dyslexia Association’s publication Perspectives on Language, entitled “Vision Efficiency Interventions and Reading Disability,” by a well-known dyslexia researcher and a pediatric optometrist.
Dr. Young has no financial interest in any dyslexia evaluation or remediation program, method, or company, including Lexercise.
If you have questions or need a referral to a qualified clinician, contact us at Info@Lexercise.com or 1-919-747-4557.
Sandie is a speech-language pathologist with more than 30 years of experience in the private practice sector. She is Visiting Assistant Professor of Communication Sciences & Disorders at University of North Carolina Greensboro, and founder/owner of the Language & Learning Clinic, PLLC, a private practice in Elkin, NC, and Greensboro, NC, specializing in communication disorders, including disorders of reading and written language.