Vision therapy (VT) - also known as visual training, vision training, visual therapy, or orthoptics - is a group of techniques
attempting to correct or improve presumed ocular, oculomotor, visual processing and perceptual disorders. Vision therapy encompasses a wide variety of non-surgical methods, which may be divided into two broad categories: (1) orthoptic vision therapy, also known as orthoptics, and (2) behavioral vision therapy, also known as behavioral or developmental optometry.
* Orthoptics aims to treat binocular vision disorders such as strabismus (eye turns), diplopia (double vision), problems with convergence (eyes turning in), and accommodation (eye focusing).
* Behavioral vision therapy treats additional problems including difficulties of visual attention and concentration, which may manifest as an inability to sustain focus or to shift focus from one area of space to another. The ability to shift the focus of visual attention from one place to another affects many aspects of life, including reading, most vocations, and most hobbies.
Eye doctors may also prescribe vision therapy to those who suffer from eye strain and visually-induced headaches; however, not all such therapy is limited to disorders of the visual system. Professional athletes, for example, may use vision therapy to enhance sensitivity to peripheral vision on the playing field or increase responsiveness to fast moving objects.
There is widespread acceptance of orthoptic therapy. Patients who experience eyestrain, "tired" eyes, or diplopia (double vision) while reading or performing other near work, and who have convergence insufficiency may benefit from orthoptic treatment.
Major optometric organizations, including the American Optometric Association, the American Academy of Optometry, the College of Optometrists in Vision Development, and the Optometric Extension Program, support the assertion that vision therapy does not directly treat learning disorders, but rather addresses underlying visual problems which are claimed to affect learning potential.
Advocates cite a number of indications for the use of vision therapy. Some assert that poor eye tracking affects reading skills, and that improving tracking can improve reading.
In 1988, a review of 238 scientific articles was published in the Journal of the American Optometric Association defining vision therapy as "a clinical approach for correcting and ameliorating the effects of eye movement disorders, non-strabismic binocular dysfunctions, focusing disorders, strabismus, amblyopia, nystagmus and certain visual perceptual (information processing) disorders." The paper concluded, "It is evident from the research that there is scientific support for the efficacy of vision therapy in modifying and improving oculomotor, accommodative, and binocular system disorders, as measured by standardized clinical and laboratory testing methods for patients of all ages for whom it is properly undertaken and employed."
Convergence insufficiency is a common binocular vision disorder characterized by asthenopia, eye fatigue and discomfort. Asthenopia may be aggravated by close work and is thought by some to contribute to reading inefficiency. In 2005, the Convergence Insufficiency Treatment Trial published two large, randomized clinical studies examining the efficacy of orthoptic vision therapy in the treatment of symptomatic convergence insufficiency. Although neither study examined reading efficiency or comprehension, both demonstrated that in-office vision therapy was more effective than "pencil pushups" (a commonly prescribed home-based treatment) for improving the symptoms of asthenopia and the convergence ability of the eyes. The design and results of at least one of these studies has been met with some reservation, questioning the conclusion as to whether intensive office-based treatment programs are truly more efficacious than a properly implemented home-based