Effect of Oculomotor Therapy on Convergence Insufficiency and Postural Control: Protocol for a Randomized Clinical Trial

Abstract

Background: Convergence insufficiency (CI) is a binocular vision disorder that impairs the ability to sustain near focus, causing symptoms such as diplopia, visual fatigue, and headaches. Evidence also links CI to postural control deficits, suggesting it may be an underestimated risk factor for balance instability. However, this relationship remains unclear in the literature. Aims: To investigate the effects of oculomotor therapy on binocular convergence and postural control in adults with convergence insufficiency (CI). Materials and Methods: This will be a randomized controlled clinical trial, with a total of 48 participants with a confirmed diagnosis of CI. Participants will be randomly allocated to two groups: Experimental Group (EG, n=24) which will receive oculomotor therapy, and Control Group (CG, n=24) which will have no intervention. Oculomotor therapy will include exercises such as Brock String, Barrel Card, Life Saver Card (Dynamic Convergence Training), Saccadic and Pursuit Eye Movement Exercises, and Modified Pencil Push-Up. Assessments will occur at three time points: baseline (prior to the intervention), immediately after the five-session intervention (once per week), and at a 30-day follow-up. The primary outcomes will be ocular convergence capacity, assessed using the Near Point of Convergence (NPC) test, and functional mobility, evaluated using the Timed Up and Go (TUG) test. Secondary outcomes include CI-related symptomatology, assessed using the Convergence Insufficiency Symptom Survey (CISS), Quality of Life (SF-36), and postural control (Stabilometry) using a force platform. Results: Analysis will be by intention-to-treat using a linear mixed model approach to account for potential participant dropouts. Comparisons between groups before and after treatment will demonstrate whether oculomotor therapy has a significant effect on binocular convergence capacity and postural control. The data will be published after the study is completed. The study may support the incorporation of oculomotor rehabilitation into broader therapeutic strategies aimed at preventing falls and improving functional autonomy. This protocol was registered (NCT07036263) and received ethical approval (CAEE: 79397224.2.0000.5511).