Do Coloured Filters Work?

Research on the use of coloured filters for people with visual stress is described in this chapter. There is a sizeable body of research, and the chapter concentrates on systematic reviews and randomised controlled trials. The use of coloured lenses in those with reading difficulties remains controversial, and reasons for the controversy are discussed. It is argued that it is only in a minority of individuals with reading difficulties (those with visual stress) that the treatment is likely to be successful.