This is a broadly defined visual perceptual disorder affecting primarily reading and writing based activities. Because of this it is sometimes categorized as a form of dyslexia. However, bestselling author, Donna Williams, in her book, Like Colour To The Blind, wrote about her experience with tinted lenses after being diagnosed with Irlen Syndrome. In this book she describes the lenses as enabling her to have cohesive , unfragmented vision, able to see faces, bodies, and objects as a whole for the first time and reducing the extremity of experiences like meaning-blindness, face blindness, inability to learn to read facial expressions and body language and the social consequences of these impairments. This led to a worldwide raised awareness of Irlen Syndrome as a sensory perceptual problem common in many (but not all) people with autism and expanded awareness of the potential effects far beyond that of reading disability, also leading to awareness of fluorescent lighting on those with this perceptual disorder.
Symptoms include light sensitivity and contrast problems. People with strong symptoms find it very difficult to read black text on white paper, particularly when the paper is shiny. Also restricted field of clear vision, poor depth perception, attention and concentration difficulties, context blindness and poor object recognition, and seeing part and losing the whole.