Outcome of occlusion treatment for amblyopia

The purpose of this study was to determine the level of visual acuity following occlusion treatment for strabismic and anisometropic amblyopia and to analyze the factors that influence the outcome.

In this observational study, we examined the medical records of 246 patients discharged between April 1991 and March 1996, including those who failed to complete treatment. Two groups were identified: Group 1 esotropia (n = 151); and Group 2 anisometropic amblyopia with or without microtropia (n = 79). Factors influencing outcome of treatment were analyzed, success being defined as 6/12 or better in the amblyopic eye.

In Group 1, 85% achieved 6/12 or better in the worst eye (linear acuity test), 15% achieved less than 6/12. (73% achieved 6/9 or better, 16% achieved 6/12 or 6/18, and 11% achieved less than 6/18). In group 2, 95% achieved 6/9 or better in the worst eye (linear acuity test); 5% achieved 6/12.

Outcome was better than other full population studies to date. A good visual outcome was achieved in all cases of pure anisometropic amblyopia. Significant factors influencing outcome in the esotropic group were compliance, anisometropia, and visual acuity at start of treatment. An occlusion protocol is suggested aimed at further improving compliance and outcome.