Irlen syndrome, occasionally referred to as scotopic sensitivity syndrome (SSS) or Meares–Irlen syndrome, is a postulated disorder of vision or image-processing in the brain. Irlen syndrome is also sometimes referred to as asfedia or visual stress. Many mainstream professionals are skeptical of the concept. Research on Irlen syndrome has produced mixed results, finding a possible neurological basis for the condition but little or no evidence supporting the most commonly proposed treatment using tinted eyeglasses or overlays to aid reading. History
In 1980, New Zealand teacher Olive Meares described the visual distortions some individuals reported when reading from white paper. In 1983, American psychologist Helen Irlen wrote a paper about the use of coloured overlays aiding the reading abilities of some people. Similar symptoms were separately described by Meares and Irlen, each unaware of the others work. Irlen, who was the first to systematically define the condition, named her findings "scotopic sensitivity", though in the discussions and debates over the following years, some referred to it as Meares-Irlen syndrome. The Irlen Institute, founded by Helen Irlen, describes scotopic sensitivity as "a perceptual processing disorder" related to brain interpretations of colours and light.It remains controversial whether non-Irlen-certified Meares-Irlen syndrome and the original Irlen syndrome are the same condition. Irlen syndrome, for example, seems to include a broader array of symptoms, including severe variants of the core condition.
Irlen syndrome was also studied in Australia by Greg Robinson (1944–2008) at the University of Newcastle. He was director of the Special Education Centre at the School of Education.In the US, peer-reviewed literature on the topic suggests that much is unknown about the cause of these disorders, ranging from the 2011 study in a journal of the American Academy of Pediatrics, "Irlen Colored Overlays Do not Alleviate Reading Difficulties" and the 2012 study in the journal Brain Topography, "A Functional Neuroimaging Case Study of Meares–Irlen Syndrome". The first, purely in relation to Meares-Irlen syndrome, finds that there is no evidence for one of the fundamental claims of therapeutic benefit. The second, which focused primarily on Irlen syndrome, found compelling evidence of unique brain function linked to the syndrome. Treatment
The College of Optometrists (UK) has specified guidelines for optometrists who use the colorimeter system. A society for coloured lens prescribers has been established to provide a list of eye-care practitioners with expertise in the provision of coloured lenses for the treatment of visual stress. Irlen Method
The Irlen Method uses coloured overlays and tinted lenses in the form of glass or contact lenses. The method is intended to reduce or eliminate perceptual processing errors; it is claimed the resultant retiming of visual signals in the brain improves the reading difficulties associated with scotopic sensitivity syndrome.