Risk Factors for Failure of Amblyopia Treatment in Patients with Anisometropic Amblyopia

Abstract

Abstract: : Purpose: Anisometropia is an important cause of amblyopia. Little formal research has been done to investigate factors that might influence the outcome of treatment by the conventional methods (occlusion or penalization therapy). The purpose of this study was to investigate factors that might predict success or failure of therapy. Methods: We retrospectively reviewed the charts of 104 children with anisometropic amblyopia that met our inclusion criteria of age between 3 and 8 years at the initiation of treatment, a difference in the vision between the two eyes of at least 3 logMAR acuity lines, vision in the amblyopic eye of at least 20/50, and no ocular structural abnormalities. Success was defined as a final vision in the amblyopic eye of at least 20/40. Results: Children in this study had an average age of 4.8 years +/- 1.5 years, and 30 (28.8%) were 6 to 8 years old. Fifty-nine (56.7%) were males. Seventy-six patients (73%) had vision of 20/70 or worse in the amblyopic eye. The mean duration of follow-up was 26 months. Failure risk factors were: age above 6 at the onset of (P = 0.020, unadjusted odd ratio (95% CL) = 2.84 [1.18, 6.83]), concurrent strabismus (P = 0.036, unadjusted odd ratio (95% CL) = 2.45 [1.06, 5.65]), and initial visual acuity in the amblyopic eye of 20/200 or worse (P = 0.038, unadjusted odd ratio (95% CL) = 2.61 [1.05, 6.46]). Neither the type or the degree of refractive error nor the difference in the refractive power between the two eyes was a significant risk factor for treatment failure. Conclusions: The risk for failure of amblyopia treatment in children with anisomertropia increased with age above 6 years at the onset of treatment and initial visual acuity of 20/200 or worse. Failure risk was also higher in anisometropic patients with concurrent strabismus. The clinical profile of patients with anisometropic amblyopia may be useful in predicting response to therapy.

Keywords: amblyopia