By Patti White
AALRC Disabilities Project Manager

The AALRC and the Arkansas Optometric Association continue to support and promote the use of the Vision Therapy Assessment (VTA) software screening for adult education and literacy students who report vision problems or significant problems with reading. While some programs report an increase in reading performance for students who use Irlen filters (colored overlays), the American Optometric Association 1998 position statement on "the use of tinted lenses for the treatment of dyslexia and other related reading and learning disorders" states that there is currently no scientific research to support the ‘scotopic sensitivity syndrome' hypothesis. The current focus on accountability and research-based practices by the US Department of Education, Office of Vocational and Adult Education, further supports the AALRC position to affirm its support of methods that have proven to be effective by valid research.

There have been a number of studies over the years that have attempted to replicate the results of the initial research by Helen Irlen, who refers to her abstract presented in 1983, but has never published the details of her research. The problems with the literature that have been the focus of subsequent studies include:

One 1990 pilot study showed that while vision therapy resulted in statistical improvement in vision functioning, Irlen filters did not result in significant gains in reading rate, word recognition in context, or comprehension (Blaskey, et al, Journal of Learning Disabilities, December 1990). A cohort study about dyslexic children in 1993 reported that, "...there was no reliable correlation between subjective lens preference and objective reading performance. These findings challenge not only the potential efficacy of tinted lenses in treating dyslexia, but also the subjective method on which this treatment is primarily based" (Monacker, et al, Arch Opthalmology, Februrary 1993). A study of the placebo effect in Australia found that, "The failure to find significantly greater improvement for the experimental groups over the control group for the total period, despite subjects' reports of improved print clarity, may be partly related to the lack of effective letter-sound analysis and synthesis skills and to the use of a word-identification strategy of guessing based on partial visual analysis" (Robinson, Perceptual and Motor Skills, February 1999). Several of the studies' conclusions echo those of Mitchell Scheiman, O.D., whose 1989 study concluded that "...underlying vision problems are responsible for the symptoms of individuals who feel they are candidates for Irlen Filters....these should be treated using conventional optometric therapy including lenses, prisms, and vision therapy" (Scheiman et al, 1990).

The AALRC encourages further research to investigate the effect of Irlen lenses and filters on reading, but until the research is documented, supports the use of the VTA software screening as a scientificallybased, effective, and appropriate tool for vision screening—and supports vision therapy as a scientificallybased, effective, and appropriate tool for addressing many vision problems that impact reading skills.

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