2017 Glenn A. Fry Award Lecture: Establishing an Evidence-based Literature for Vision Therapy - A 25-year Journey

Abstract

In this article, I summarize the 2017 Glenn A. Fry Award Lecture and my journey from student, to clinician, to optometric educator, and finally researcher/vision scientist. Although content for many years of teaching and practicing vision therapy, the era of evidence-based health care created a level of discomfort, as it became evident that my area of interest, vision therapy, had minimal quality evidence to support its use. Joining forces with a group of exceptional colleagues, we established the Convergence Insufficiency Treatment Trial Investigator group, and we were able to achieve funding from the National Eye Institute for multiple randomized clinical trials. The results of our studies demonstrate that vision therapy is an effective treatment option for convergence insufficiency in children, and office-based therapy is more effective than home-based therapy. These studies also demonstrated that home-based pencil push-ups commonly used by both optometrists and ophthalmologists are no more effective than placebo therapy. More recently, working in a new arena of objective recording of vergence, accommodative, and versional eye movements, my research has demonstrated that objective outcome measures of vergence are feasible for future randomized clinical trials. In pilot studies with both naturally occurring convergence insufficiency and concussion-related convergence insufficiency, statistically significant and clinically meaningful changes have been found in both disparity vergence peak velocity and response amplitude after office-based vision therapy. With new evidence about the high prevalence of concussion-related convergence insufficiency, there is much work to be accomplished to study the effectiveness of vision therapy for convergence insufficiency as well as the underlying mechanisms for how and why vision therapy is effective.

Figure 1

(A) Comparison of final NPC values for office-based vision therapy vs placebo, home-based pencil push-ups vs placebo, home-based computer vergence therapy vs placebo from recent randomized clinical trials. Any value below the black horizontal line is a normal value. (B) Comparison of final PFV values for office-based vision therapy vs placebo, home-based pencil push-ups vs placebo, home-based computer vergence therapy vs placebo from recent randomized clinical trials. (C) Comparison of final CISS values for office-based vision therapy vs placebo, home-based pencil push-ups vs placebo, home-based computer vergence therapy vs placebo from recent randomized clinical trials. Any value below the black horizontal line is a normal value.

Figure 2

Each colored trace is an individual convergence eye movement response to a 4° symmetrical binocular disparity vergence step stimulus from a non-symptomatic binocularly normal control participant.

Figure 3

(A-B) Each gray line is an individual eye movement response from a 4° symmetrical binocular disparity vergence step stimulus. The blue traces show the average position before office-based vision therapy for a subject, and (B) shows the same data after office-based vision therapy for the subject.