The Association Between Improvement of Stereoacuity and Suppression in the Treatment of Anisometropic Amblyopia

PURPOSE: To investigate the association between stereoacuity and suppression during occlusion therapy for patients with anisometropic amblyopia. DESIGN: Retrospective study. PATIENTS AND METHODS: This study included 19 patients with hyperopic anisometropic amblyopia who underwent occlusion therapy. The mean age of the patients was 5.5 ± 1.4 years. The participants were evaluated for improvement in stereoacuity and suppression before beginning occlusion therapy, when the highest amblyopic visual acuity (VA) was achieved, during tapering, at the end of occlusion therapy, and at the final visit. Stereoacuity was evaluated using the TNO test or JACO stereo test. The presence of suppression was evaluated using circle No. 1 of the Stereo Fly Test or JACO results as the optotype. RESULTS: Of the 19 patients, 13 (68.4%) had suppression before occlusion, eight (42.1%) when the highest VA was achieved, five (26.3%) during tapering, and none at the final visit. Of the 13 patients with suppression before occlusion, 10 (76.9%) showed further improvement in stereoacuity when suppression disappeared, and nine had foveal stereopsis of 60 arcseconds. A significant association was confirmed between foveal stereopsis and suppression when the highest VA was achieved and during the tapering period (P<0.05, Fisher’s exact test). CONCLUSION: Suppression was observed even when the VA in amblyopic eyes reached the highest score. By gradually decreasing the duration of occlusion, suppression was eliminated, leading to the acquisition of foveal stereopsis.