Comparison of three vision therapy approaches for convergence insufficiency

Purpose: We compared the effectiveness of three active vision therapy approaches for convergence insufficiency (CI). Methods: This randomized clinical trial included patients meeting the eligibility criteria and with symptomatic CI, who were allocated into three groups. In the home-based vision orthoptic therapy (HBVOT) group, patients performed the pencil push-up procedure 15 min/day for 5 days/week. In the office-based vision orthoptic therapy (OBVOT) group, patients underwent 60-min orthoptic therapy using a major amblyoscope twice weekly with additional home orthoptic therapy. In the augmented office-based vision orthoptic therapy (AOBVOT) group, patients performed orthoptic exercises using 3-diopter over-minus lenses and a base-out prism in addition to major amblyoscope therapy, and additional home reinforcement was prescribed during the same time period. Results: All 84 subjects (mean age, 26.8 ± 8.3 years) showed a statistically significant improvement in near exophoria, positive fusional vergence (PFV) at near, near point of convergence (NPC), stereoacuity, and Convergence Insufficiency Symptom Survey (CISS) scores at follow-up. Exophoria decreased by 64%, 68%, and 85% in the HBVOT, OBVOT, and AOBVOT groups, respectively (P = 0.2). PFV increased by 68%, 100%, and 100% in the HBVOT, OBVOT, and AOBVOT groups, respectively (P < 0.001). NPC decreased (improved) by 86%, 89%, and 96% in the HBVOT, OBVOT, and AOBVOT groups, respectively (P = 0.4). The CISS scores decreased by 75%, 96%, and 100% in the HBVOT, OBVOT, and AOBVOT groups, respectively (P = 0.003). Conclusion: Our results showed that in adults with CI, the augmented office-based orthoptic treatment was relatively more effective than the other treatments.