Longitudinal investigation of disparity vergence in young adult convergence insufficiency patients

Vergence is a form of eye movement in which the eyes move in opposite directions to minimize retinal disparity. It allows an object at different distances from a viewer to appear single during binocular vision by centering the image on the fovea of each retina. Convergence insufficiency (CI) is a binocular disfunction in which blurry and double vision is a symptom. Office-based Vergence/Accommodative Therapy (OBVAT) has been shown to be effective in treating CI. A randomized clinical trial was designed to study fifty participants with CI before and after therapy using randomized therapy treatment (active and placebo), standardized clinical definitions, and a masked clinician to measure clinical outcomes. A haploscope was used to independently show stimuli to the left and right eye of the participants. A video-based eye tracker was used to capture eye-movement data, and a custom MATLAB program was used to analyze the following data parameters: latency, time to peak velocity, peak velocity, and final amplitude. Eye-movement data parameters significantly improved post OBVAT when comparing baseline and post treatment results. The results after Office-Based Placebo Therapy (OBPT) were compared to OBVAT results, and a statically significant difference was found. Results support that OBVAT leads to a significant improvement in vergence dynamics post therapy compared to baseline measurements