In the early 1980's, Helen Irlen discovered a perceptual problem caused by light sensitivity. She found that it could be successfully treated by the use of coloured lenses. The full spectrum of light causes distortions with print and the environment.
People can suffer from eyestrain, tiredness, stress, headaches and migraine.
Some people cannot judge heights, distances and speeds, which makes them clumsy and accident prone. Black print on white paper can be a major problem for those with Irlen Syndrome. Print can appear distorted, blurry, broken up or even moving on the page. In some cases there is only a small area on the page which is clear because of a restricted span of focus. Without treatement, there is little chance for those who suffer in this way, of ever finding reading easy or comfortable.