Tinted lenses and related therapies for learning disabilities--a review.

Research relating to the use of Irlen tinted lenses and coloured overlays for underachievers is reviewed. Many of the studies were not published in refereed journals and were methodologically poor. The weaknesses of the Irlen argument are discussed, including the absence of evidence to support the claims that these tints need to be uniquely prescribed and manufactured. Syntonics is another form of visual colour therapy that has been applied to those with a learning disability. Research on this is reviewed, and is also shown to have procedural irregularities which preclude firm conclusions. Owing to the poor quality of much of this research the claims of the protagonists of these therapies cannot be proved or disproved. A proposed new therapy is normally preceded by a valid theoretical hypothesis; this has been lacking in the present topic. Recently, a feasible explanation has been proposed in terms of 'pattern glare' resulting from mild hypersensitivity to epileptogenic patterns. This, together with potential alternative theories, is discussed. In the conclusion of this review, advice is given for eye-care practitioners who may be consulted on these therapies.