Reading Disabilities
and Irlen Tinted Filter Lenses

Have you heard of tinted lenses as a remedy for reading disabilities, rapid fatigue when reading, headaches, sore eyes and poor depth perception? For more than fifteen years this new technique has been available in Australia with some very exciting results. The technique uses precisely prescribed tinted filter lenses to correct perceptual disorders which often cause reading disabilities.

The technique was developed in the early 1980s by Professor Helen Irlen, a Californian psychologist. She was the director of a research project, investigating adult reading disabilities at the University of California. She was talking with a group of adults who had severe reading difficulties. Their comments prompted her to ask them what the reading page looked like to them and she was astonished by some of the comments they made. Around her she was hearing people saying, "That's what I see too! When I tell my family, they laugh at me." They described how the letters on the page seemed to move around, how the white page strained their eyes, how they saw streaks of white on the page, how the print went blurry, how they saw ghosting of letters etc.

Since 1986 over 80,000 children and adults world wide have been prescribed Irlen lenses. Most have been people with reading disabilities ranging from severe to mild, while others suffered from chronic glare headaches and Chronic Fatigue Syndrome. Some have visual disorders and reading problems resulting from head injuries due to an accident, or to central nervous system infections and some have Autism Spectrum Disorder. The technique is seen as the biggest breakthrough in assisting individuals with learning disabilities for more than twenty years.

It must be stressed that this method does not help every person with reading disabilities. Recent research indicates that approximately 60% of individuals, both children and adults, who find reading difficult, fatiguing or stressful, can be helped considerably with Irlen tinted filter lenses. When one considers that recent research on adult literacy in Australia, shows that between 15% and 20% of all adults, or more than 1.5 million adults, are functionally illiterate, then the number of people who might benefit from the lenses is apparent. All the more reason why children at school, especially in primary school, should be screened if they are struggling with reading skills or they avoid reading consistently.

Helen Irlen called this disorder "Scotopic Sensitivity". Essentially it is a specific sensitivity of the visual system to certain frequencies within the white light spectrum. This appears to be an inherited disability which causes rapid fatigue of the visual system resulting in a range of symptoms, most of which interfere with effective and efficient reading performance.

It should be stressed that these symptoms persist despite thorough optometric assessment and the wearing of prescription lenses.

However, prior to assessing a client for Irlen lenses, a recent optometric assessment is recommended. This is to ensure that any refractive or astigmatic problems have been corrected. The individualised Irlen tint can only be added to existing prescription lenses if they have been manufactured according to our precise specifications. Often, some optometrists prescribe low-powered stress lenses for children with reading difficulties. Sometimes this is quite helpful, but it rarely solves a serious reading difficulty.

There are still many "sceptics" within the community. When the lenses were first used, there was very little scientific evidence to support the theory. However there are now over a hundred research publications on Irlen tinted lenses, including research from Harvard Medical School and the Canadian Medical Association.

A recent breakthrough in research on dyslexia at Harvard University clearly links disorders in a person's visual perception as a major cause. A team of neuroscientists, lead by Dr Margaret Livingstone has reported research in the prestigious research journal "Proceedings of the American Academy of Sciences". Their findings show that Visual dyslexia is the result of the failure of the visual perceptual system's neuro-circuits to keep proper timing. They also reported that coloured filters can correct this imbalance and so reduce the effect of dyslexia, such as chronic loss of place, reversing words, blurred vision, movement of the print and rapid fatigue when reading.

Dr Drake Duane, an authority on dyslexia and learning disorders at the Arizona State University, states that this research provides "convincing evidence that the nervous system of those who are dyslexic are atypical and provides theoretical support for one treatment of dyslexia through the use of coloured filters for reading".

Dr Galaburda, Director of the Dyslexia Neuro-anatomical Centre at Beth Israel Hospital in Boston, views this research breakthrough as indicating that the visual system consists of two major neural pathways. "One of these pathways, the magnocellular system, is composed of large cells that carry out fast processes and is used for seeing motion, stereoscopic vision, depth perception, low contrast and locating objects in space. The second pathway, the parvocellular system, is composed of smaller cells that carry out slower processes. It specialises in colour, detailed forms, high contrast and stationary images." Dr Galaburda explains that a neurological timing imbalance or 'sluggishness' in the timing between these two systems leads to visual dyslexia.

This is because of the visual perceptual demands of the reading process, usually in situations of high contrast of black print on white paper. It also accounts for why a significant number of people with reading difficulties have poor depth perception and are clumsy. In essence, the disturbed synchronisation of the two visual perceptual pathways leads to these perceptual disorders. Autopsies conducted by Dr Galaburda on the brains of ten deceased people, five known dyslexics and five normal readers, showed distinct anatomical cell differences (in size) when the parvocellular and magnocellular cells were compared.

Professor Mary Williams, University of New Orleans, has completed research which indicates that the 'sluggish' timing or lack of synchronisation of these two visual pathways in dyslexic children is corrected with the use of coloured filters.

Dr Solman, a research psychologist and Professor Dain, a research optometrist, both at the University of New South Wales, recently published research that also provides strong evidence that contrast sensitivity of white to black when reading print on white paper, was a significant factor in creating reading perceptual disorders. Also coloured filters that were specifically prescribed for particular reading disabled children, dramatically reduced sensitivity and improved reading.

From this recent research evidence, there can no longer be any doubt that Helen Irlen was correct. Carefully and precisely prescribed spectrally modified, Irlen tinted filters substantially reduce perceptual disorders for those children and adults who have this visual perceptual dysfunction she calls "Scotopic Sensitivity / Irlen Syndrome".