Coloured Lenses Do Not Cure Reading Disability

The Edmonton Journal (August 17, 2013) included an article on a private members’ bill promoting testing for Irlen Syndrome in schools. Medical professionals heavily oppose the bill and I thought I should add my voice to the opposition as an educational professional. I also hope to challenge some of the arguments made in the article about the understanding or existence of scientific studies, and move the discussion to a more scientific (and skeptical) direction.

Irlen Syndrome, Meares-Irlen Syndrome, visual stress, or Scotopic Sensitivity Syndrome (as it should be called), is probably a legitimate condition (there is an argument that all symptoms related to it are really symptoms of other eye issues, but I am not an expert on that) that affects a very small proportion of students. Unfortunately, there are no good epidemiological studies on how many are affected, but the best estimate I have found is between 1 and 3%, most of whom are not severe cases. Contrary to suggestions by Irlen and her followers, Irlen Syndrome is not an explanation of reading difficulties – the best information we have is that there is possibly a slightly higher incidence rate (maybe closer to that 3% mark) of visual stress among poor readers than among normally reading individuals. This would not be surprising as poor readers often have many other comorbid neurological issues; however, these numbers are from a study of adults, and the direction of the effect, at that point, is not clear any longer. Naturally experiencing visual stress, particularly if it is severe, can affect reading development. Still, it does not, for example, cause dyslexia or explain reading problems of the remaining 97% or more of poor readers. It is very disappointing to see people, who sell the product to great profit, argue in press that half of poor readers suffer from visual stress – there is no research, good or bad, to support that argument. My own experience with over 200 poor readers is that one or two of them likely suffered from visual stress and articulated the symptoms very eloquently. Many had tried coloured overlays and felt that they had no impact after the novelty subsided.

Teachers, reading specialists, or "Irlen specialists" should not diagnose visual stress as they have no reliable and valid means of doing so, and the latter have a large financial incentive to find as many cases as possible (and they do!). All the available questionnaires that I have been able to examine confound poor reading and visual stress; in other words, they ask questions about both sets of symptoms to diagnose visual stress. Asking kids to try coloured overlays while reading is also not a valid means of diagnosing visual stress, as it confuses the real effect and the placebo effect that is always there. In my opinion, visual stress needs to be diagnosed by ophthalmologists, and probably only after a long process of elimination of other more common visual syndromes.

In terms of the common treatment, coloured overlays or glasses, there is no scientific evidence that they work beyond an initial novelty period. I have looked at all the published intervention studies that we were able to locate. It is clear that when you do carefully examine the evidence and quality of the studies, the best available evidence is conclusive in that coloured overlays do not improve reading. This does not mean that there are no individuals for whom they work, but that at most, they are a small minority of poor readers. The same conclusion is reached whether you examine poor readers that are screened to have visual stress or not.

Having said that, there is also no evidence that coloured overlays do harm. Because they introduce a novelty factor to the reading task, they may be enough to get a reluctant and struggling reader to start practicing more. While coloured glasses can be very expensive, overlays are not, and I see no harm for a teacher having a collection of them and letting children play with them – most children will stop using them very quickly. Anything that gets children reading, no matter what colour the text is, is a good thing. However, you have to consistently keep in mind that you are not remediating real reading disabilities with overlays, and the fact that a child is using them says nothing about the child suffering from visual stress. If coloured overlays are your “remediation” for poor reading instead of teaching practices that do have scientific evidence to support them, you are in serious conflict with everything we know about the causes of reading difficulties and how to treat them.

Finally, as a parent, I take my children to have an eye exam every year and that eye exam seems to be paid either by my coverage or the province (I haven't asked but it seems to be free). If the Irlen people believe that there is something missing from these exams, they should be talking to ophthalmologists, not to schools, as any eye problem is primarily a medical issue and not an educational issue per se. I have never run into a teacher diagnosing Irlen syndrome, but I think to do so is irresponsible to the extreme and opens up all sorts of problems if some parents take them seriously, and end up spending large sums of money for lenses and training that are very unlikely to help their child (and when there are other alternatives with more likely positive effects).

Gerein, K. (2013, August 17). Undeterred by detractors, MLA forging on with private members’ bill on eurological testing. Edmonton Journal. Retrieved from http://www.edmontonjournal.com/health/Undeterred+detractors+forging+with+private+members+bill+eurological+testing/8799761/story.html

Ritchie, S.J., Della Sala, S., & McIntosh, R.D. (2011). Irlen coloured overlays do not alleviate reading difficulties. Pediatrics, 128(4). Retrieved from http://pediatrics.aappublications.org/content/128/4/e932.full.html