Such effects arise when a person with dyslexia believes the coloured filter will enhance their reading, bringing about some changes in reading through an increase in attention, effort and motivation (at least in the short term). For example, the American Academy of Paediatrics found little to no evidence supporting the link to visual stress in explaining the reading difficulties of people with dyslexia.Īnd recent systematic reviews highlighted that any positive gains in reading may be a result of heightened motivation or placebo effects. The majority of research on this topic has found little evidence of measurable effects on reading accuracy or comprehension. The current body of research has failed to produce high-quality evidence demonstrating an improvement in reading when a coloured overlay is applied.įor example, in a rigorous double-masked design (in which neither the subject nor the experimenter knew the true diagnosis and prescribed colour), researchers from the University of Edinburgh reported that Irlen coloured overlays had no immediate effect on reading ability. Listed as one of the “ neuromyths” of education in a recent Nature Reviews article, the ability of coloured overlays to support the reading of individuals with dyslexia has been widely contested within published research. Myth versus evidenceĭespite having been actively investigated over the past 40 years, visual stress still remains unrecognised by the World Health Organization’s International Classification of Disease, the American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders and the American Optometric Association. And debate still rages surrounding the fundamental issue of which colour is needed to achieve optimal results. The simplicity of the intervention has helped it to become embedded into the practice of teachers, educational psychologists, optometrists and NHS orthoptic departments across the UK.īut disagreement among researchers still exists over the mechanisms and theory behind the filters’ effects.

It is believed that the removal of this visual stress would improve reading and facilitate the development of reading skills in the longer term and help people with dyslexia. Proponents of this theory say that prescribed coloured eyeglasses or plastic overlays could alleviate perceived visual distortions. These findings have led some researchers to theorise that visual impairments may be a cause of dyslexia. However, some have reported rates as high as 46 per cent and 76 per cent among those who are dyslexic or poor readers. Reported rates of visual stress symptoms in the general population range between 12-14 per cent. Visual stress (also referred to as Irlen or Meares‐Irlen syndrome) is a proposed perceptual disorder that results in apparent movement and distortion of text, headaches and eye strain while reading, which ultimately interferes with reading ability. As a result, someone with dyslexia will experience difficulties in associating printed letters with relevant speech sounds, thus causing reading difficulties. Research has demonstrated that people with dyslexia often have difficulty processing and representing the specific sounds of language.

It is a learning disability that has an impact on a person’s ability to learn how to read and write (despite adequate intelligence and educational opportunities). What is dyslexia?ĭyslexia is a neurological condition affecting 7-10 per cent of the population. Those who work in this field should, instead, be focusing on the delivery and promotion of evidence-based interventions, such as the systematic teaching of letter-to-sound combinations (phonics), or the provision of technology supports such as text-to-speech software. I believe that promoting the use of these coloured filters gives people with dyslexia false hope. In fact, a 2014 survey published in the British Medical Journal found that six out of eight UK dyslexia organisations were promoting such products on their websites uncritically and in an unbalanced way. What troubles me as a research specialist in dyslexia, as well as being dyslexic myself, is the proliferation and abundance of advertisements and testimonies proclaiming the effectiveness of the treatment online, including websites and magazines that are produced by nationally recognised dyslexia-focused charities. But I believe they should not be recommended as a treatment or a form of support for people with dyslexia because there is a lack of convincing scientific evidence supporting their effectiveness. These overlays are simple translucent pieces of plastic that add colour to text. It is claimed that the use of coloured filters and lenses can alleviate visual distortions for people with dyslexia.

Dyslexia color overlay