The efficacy of visual therapy: accommodative disorders and non-strabismic anomalies of binocular vision.

Questions concerning the effectiveness of therapeutic intervention designed to modify the function of an individual's visual system have been raised by professional groups, consumer groups, insurance carriers, students, educators, as well as "pure" scientists. This paper examines the available literature in order to answer the question, "Is there evidence that 'orthoptics' or 'vision therapy' causes changes in an individual's accommodative or vergence eye movement systems?" This review neither examines alternative methods of causing these changes nor provides information concerning which particular techniques are most effective, although the literature does provide such information. Certain conditions are explained to aid the student and lay-reader in understanding the literature cited. The literature cited substantiates that visual therapy can modify visual functions and also points out the relationship of these changes to the relief of certain symptoms.