Filtering specific wavelength patterns of light to suit the brains of children with reading difficulties.
In the 1980’s, Helen Irlen discovered that some children and adults could read better with coloured acetate sheets placed over text. She worked on techniques to identify those who might benefit from her method. Since then, other research has been done. Not everyone accepts that there is a condition known as “Irlen Syndrome”, however coloured sheets are quite widely used in schools. Visual perception is analysed and then coloured filters or lenses for glasses are made to enable the individual to see with clarity, stability, and comfort. Sometimes filters are issued without this analysis, with very mixed results. Recently it has been claimed that changing the main lighting in schools from traditional fluorescent to full-spectrum lighting would render filters unnecessary, though this may not be correct.
Cerium Visual Technologies, tel: 01580 765211, www.ceriumvistech.co.uk. Firm producing filters, testing kits etc., which are also claimed to relieve visual distortion in migraine and photosensitive epilepsy. Results from a number of research projects at UK universities are reported on their website, although the mechanism by which this operates is still not fully understood.
Wilkins A, & Neary C: 'Some visual, optometric and perceptual effects of coloured glasses'. Ophthalmic and physiological optics. 1991, Vol 11, pp163-171.
Wilkins A J, Milroy R, Nimmo-Smith I, Wright A, Tyrrell R, Holland K, Martin J, Bald J, Yale S, Miles T and Noakes: 'Preliminary observations concerning treatment of visual discomfort and associated perceptual distortion. 1992 'Ophthalmic and physiological optics, Vol 12 pp 257-262.
Lightstone A. et al. Both coloured overlays and coloured lenses can improve reading fluency, but their optimal chromaticities differ. Ophthalmic and Physiological Optics 1999 Jul;19(4):279-85.
Harris D, MacRow-Hill SJ. Application of ChromaGen haploscopic lenses to patients with dyslexia: a double-masked, placebo-controlled trial. Journal of the American Optometric Association 1999 Oct;70(10):629-40.
