Irlen Syndrome, also known as Scotopic Sensitivity Syndrome is a visual perceptual problem affecting the way in which the brain encodes and decodes visual information. Related to light sensitivity the symptoms can limit academic achievement and workplace efficiency. Individuals with Irlen Syndrome can see a printed page differently and find the white background bright or glary. Reading can be an tiring and frustrating activity.

Helen Irlen has a patented treatment method which uses specially formulated, coloured lenses worn as glasses or contact lenses to reduce or eliminate perception difficulties.