Effectiveness of binocular vision therapy in managing patients with intermittent exotropia.

Abstract

Purpose: Evaluating the effect of binocular vision training (BVT) on Newcastle Control Score (NCS)-Home, near stereopsis and convergence amplitudes in intermittent exotropia (IXT).

Design: Retrospective observational study.

Methods: 30 subjects diagnosed with IXT underwent online BVT with the BYNOCS® program. The BVT was divided into three phases (Phase 1, 2, and 3) for 20 sessions. The frequency was reduced to twice a week as a maintenance therapy. The vision training included antisuppression in the form of dichoptic therapy and exercises to enhance stereopsis and convergence. Evaluation of NCS-Home, Near Stereopsis, and convergence amplitude was conducted both before and after the training program.

Results: Nonparametric statistical tests were applied for the data analysis. The median age of the subjects was 14.5 years (10-22.75). Out of them, 13 were female and 17 male. The NCS-Home improved from 2 (1-3) to 0 (0-0) post BVT. The stereopsis changed from 1.48 log units (1.47-1.77) to 2.30 log units (2.07-2.47). The median convergence break point improved from 14 Prism Diopter, PD (4-20), to 38 PD (32-40). The median convergence recovery point improved from 6.25 PD (2-13.5) to 37 PD (30-40) post BVT. Wilcoxon signed-rank test showed significant improvement (P < 0.001) in all aforementioned parameters.

Conclusion: BVT for 20 online sessions is an effective method to improve control of IXT with improvement in NCS-Home, Near Stereopsis, and convergence amplitudes.