Effectiveness of binocular vision therapy in managing patients with intermittent exotropia

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

Retrospective observational study.

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.

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.

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