Comparison of the outcome of partial time occlusion therapy in strabismic versus anisometropic moderate amblyopes

Background Early in life, selective visual input disruption to one eye compromises most of the visual aspects, resulting in amblyopia, with a great social and economic effect. Despite being the easiest and most popular treatment regimen, monocular occlusion therapy is often questioned for efficacy in controlling visual abnormalities other than acuity in different etiologies of amblyopia. Purpose To find out the difference in response of moderately amblyopic, anisometropic versus strabismic eyes to partial occlusion therapy regarding visual acuity (VA), contrast sensitivity (CS), and depth of vision and find out any correlation of improvement of these parameters. Patients and methods This prospective comparative study included 49 moderately amblyopic children between 7 and 12 years of age divided into two groups: 25 anisometropic and 24 strabismic ones. Patients received 2-h parent-monitored occlusion regimen with near activity for 6 months on a monthly basis of follow-up. VA, CS, and stereoacuity were evaluated at each visit. Results Both groups showed significant improvement in VA, although the difference in the average amount of improvement was not significant (P<0.0001). Intragroup distribution of improvement was considerably different, where 9% of strabismic amblyopes achieved full visual recovery as compared with 40% of the anisometropic, and 62.5% had residual amblyopia versus 36% in the anisometropic group. CS improved significantly more in the anisometropic group (P=0.0493). Only 42% of the strabismic amblyopes improved in stereoacuity as compared with 88% of the anisometropic ones; the mean difference was not significant. In anisometropic amblyopes, initial VA correlated significantly with CS (P=0.019) and stereoacuity improvement (P=0.0133). Conclusion Moderately amblyopic anisometropic or strabismic children 7–12 years old can get benefit in different visual aspects from part-time occlusion therapy. The anisometropic amblyopes show better CS improvement and more reliable expectations of recovery that are largely dependent on the initial visual.