VTOD.org Guest Editorial: IMHO (In My Humble Opinion) November 2008

Guest Contributor David A. Goss, OD, PhD, FAAO, FCOVDA, Professor of Optometry, Indiana University School of Optometry

Just what IS "Optometric Vision Therapy"?

Simply stated, optometric vision therapy is vision therapy which is performed or directed by optometrists. Next we could ask, what is vision therapy? When I was in optometry school in the early 1970s, it was known as visual training. Later it was known as vision training, and today the term preferred by most optometrists who practice it is vision therapy. The Dictionary of Visual Science and Related Clinical Terms identifies vision therapy, vision training, and visual training as synonyms, and gives a definition as "the teaching and training process for the improvement of visual perception and/or the coordination of the two eyes for efficient and comfortable vision."(1) A joint policy statement of the American Academy of Optometry, American Optometric Association, College of Optometrists in Vision Development, and the Optometric Extension Program Foundation states that vision therapy is "a sequence of activities individually prescribed and monitored by the doctor to develop efficient visual skills and processing."(2)

Some aspects of those definitions could be emphasized. It is a "training process" to improve visual function. It is "a sequence of activities" structured in a prescribed sequence to start the patients at their initial levels of function and gradually improve their visual function by adjusting their activities as the therapy program progresses. It is "individually prescribed" to address the visual deficits that the individual patient has. And it is "prescribed and monitored by the doctor."

The definitions quoted above state that vision therapy leads to "the improvement of visual perception", "efficient and comfortable vision", and "efficient visual skills and processing". Efficient vision and optimal visual perception and processing are critical to many aspects of daily life, including reading, learning, and many occupational and recreational activities. Thus many patients successfully treated in vision therapy report better school, work or sports performance.

Vision therapy activities include various procedures with lenses, prisms, filters, occluders, specialized instruments, and visual targets which stimulate accommodation, vergence, eye movements, and other visual skills, as well as visual perception and visual processing. Because the visual system is complex and its regular function is integrated with auditory, vestibular, cognitive, and other functions, training procedures used in vision therapy can include activities which integrate other sensory and motor modalities with vision.

Vision therapy has its roots in orthoptics, which was originated by French ophthalmologist Louis Emil Javal (1839-1907).(3) Javal was first trained as an engineer and later studied vision science and medicine. Concerned about the unfavorable result of strabismus surgery for his father, he was determined to develop a non-surgical treatment for his younger sister who had esotropia.(4) Another early contributor to orthoptics was British ophthalmologist Claud Worth (1869-1936). Griffin and Grisham(5) identify three main philosophies of vision therapy, Javal and the French School, Worth and the English School, and Optometric Vision Therapy. Whereas orthoptics as developed by Javal and Worth addressed strabismus, optometric vision therapy has also addressed heterophoria, accommodative disorders, eye movement disorders, and visual processing deficiencies.

One could distinguish several schools of thought within optometric vision therapy. One classification of optometric thought on vision therapy would be into categories which we might call classical optometric vision therapy and behavioral optometric vision therapy.(6-8) The classical approach is often portrayed as a structuralist view and the behavioral approach as a functionalist view. That has always seemed simplistic and misleading to me. I don't think anyone would deny that both structure and function are important. The distinction as I see it is that the classical approach is more conservative. It relies on diagnostic and treatment strategies which tend to have direct and clear supportive evidence. The behavioral approach uses many classical techniques plus it is more likely to venture into procedures which have indirect or anecdotal support. The behavioral approach seems to be more holistic and more likely to involve techniques which integrate vision with other sensory and motor modalities.

One may ask why optometrists are more involved in vision therapy than other professionals such as ophthalmologists. As has been pointed out by Press,(9) "Ophthalmologists are expert in the surgical care of eyes and the integrity of its visual pathways, while optometrists are the experts in visual function." The optometric educational curriculum is well suited to building a strong background for directing vision therapy, with courses in such areas as sensory aspects of vision, binocular vision, ocular motility, geometrical and ocular optics, ocular anatomy, neuroanatomy, and development of the visual system, along with courses on the diagnosis and management of vision conditions.

Vision therapy is effective for the remediation of various vision conditions, as shown in several detailed literature reviews.(10-18) Some persons cite evidence based health care to deny the merits of vision therapy because randomized double-blind placebo-controlled clinical trials have not been conducted for all conditions treated with vision therapy. However, as pointed out by Sackett et al.,(19) who are among the leading proponents of evidence based health care, "The practice of evidence based medicine means integrating individual clinical expertise with the best available external clinical evidence from systematic research . . . Evidence based medicine is not restricted to randomized trials and meta-analyses. It involves tracking down the best external evidence with which to answer our clinical questions."(19) Until all the randomized clinical trials are performed to remove lingering doubts about the effectiveness of vision therapy, as has now been done for convergence insufficiency,(20) there is enough current evidence that vision therapy should be made available to patients who would benefit from it.

References

• 1. Hofstetter HW, Griffin JR, Berman MS, Everson RW, eds. Dictionary of Visual Science and Related Clinical Terms, 5th ed. Boston: Butterworth-Heinemann, 2000:558.
• 2. Williams GJ, Cotter SA, Hoffman LG, et al. Vision therapy: information for health care and other allied professionals. J Am Optom Assoc 1999;70:428-430.
• 3. Press LJ, The evolution of vision therapy. In: Press LJ, ed. Applied Concepts in Vision Therapy. St. Louis: Mosby, 1997:2-8.
• 4. Revell MJ. Strabismus: A History of Orthoptic Techniques. London: Barrie & Jenkins, 1971:15.
• 5. Griffin JR, Grisham JD. Binocular Anomalies: Diagnosis and Vision Therapy. Amsterdam: Butterworth-Heinemann, 2002:263-268.
• 6. Birnbaum MH. Optometric Management of Nearpoint Vision Disorders. Boston: Butterworth-Heinemann, 1993:283-286.
• 7. Birnbaum MH. Behavioral optometry: a historical perspective. J Am Optom Assoc 1994;65:255-264.
• 8. Press LJ. Models of vision and their therapeutic implications. In: Press LJ, ed. Applied Concepts in Vision Therapy. St. Louis: Mosby, 1997:21-28.
• 9. Press LJ. Letter to the editor: The interface between ophthalmology and optometric vision therapy. Bin Vis Strab Quart 2002;17:81.
• 10. Suchoff IB, Petito GT. The efficacy of visual therapy: accommodative disorders and nonstrabismic anomalies of binocular vision. J Am Optom Assoc 1986;57:119-125.
• 11. Garzia RP. Efficacy of vision therapy in amblyopia: a literature review. Am J Optom Physiol Opt 1987;64:393-404.
• 12. Griffin JR. Efficacy of vision therapy for nonstrabismic vergence anomalies. Am J Optom Physiol Opt 1987;64:411-414.
• 13. Rouse MW. Management of binocular anomlies: efficacy of vision therapy in the treatment of accommodative deficiencies. Am J Optom Physiol Opt 1987;64:415-420.
• 14. Cohen AH, Lowe SE, Steele GT, et al. The efficacy of optometric vision therapy. J Am Optom Assoc 1988;59:95-105.
• 15. Grisham JD. Visual therapy results for convergence insufficiency: a literature review. Am J Optom Physiol Opt 1988;65:448-454.
• 16. Cooper JS, Burns CR, Cotter SA, Daum KM, Griffin JR, Scheiman MM. Care of the Patient with Accommodative and Vergence Dysfunction, American Optometric Association Clinical Practice Guideline. St. Louis: American Optometric Association, 1998.
• 17. Ciuffreda KJ. The scientific basis for and efficacy of optometric vision therapy in nonstrabismic accommodative and vergence disorders. Optom - J Am Optom Assoc 2002;73:735-762.
• 18. Bonilla-Warford N, Allison C. A review of the efficacy of oculomotor vision therapy in improving reading skills. J Optom Vis Dev 2004;35:108-115.
• 19. Sackett DL, Rosenberg WMC, Gray JAM, et al. Evidence-based medicine: what it is and what it isn't: It's about integrating individual clinical experience and the best external evidence. Br Med J 1996;312(7023):71-72.
• 20. Scheiman M, Cotter S, Mitchell GL, et al. Randomized clinical trial of treatments for symptomatic convergence insufficiency in children. Arch Ophthalmol 2008;126:1336-1349.