Risk Factors for Amblyopia in Congenital Anterior Lens Opacities

Purpose: We sought to identify the features of congenital anterior lens opacities (CALOs), which are associated with increased risk for amblyopia. Methods: We undertook a retrospective study of 59 patients with CALO from 3 clinical practices. The following variables were examined: type (polar, subcapsular, or pyramidal), location (central, paracentral, or peripheral), diameter, presence of adherent iris tissue, anisometropia (spherical equivalent), unilateral versus bilateral, and presence or absence of amblyopia. Pearson chi-square and independent sample t-tests were conducted to evaluate if any of the aforementioned variables were independently associated with amblyopia. Relative risk was then calculated for significantly related variables (P < 0.05). Results: Amblyopia was present in 17 of 59 patients (28.8%). Patients with amblyopia had a mean anisometropia of 1.23 diopters whereas nonambyopic patients had a mean anisometropia of 0.25 (P = 0.023). The relative risk for amblyopia with anisometropia of one diopter or greater was 6.5 (95% confidence interval = 3.79-7.45). The mean cataract size in the amblyopic eyes was 1.22 mm (range, 0.7-2.0 mm). Mean cataract size in the nonamblyopic eyes was 0.95 mm (range, 0.5-2.0 mm). This difference in mean cataract size was significant with independent sample t-tests (P = 0.02); however, this difference did not remain significant with logistic regression. Cataract size was not a significant relative risk factor for amblyopia. Conclusions: Our overall incidence of amblyopia was 28.8%. The only variable associated with increased relative risk for amblyopia in this group of patients was anisometropia. Patients with CALO who have anisometropia of 1 diopter or greater are 6.5 times more likely to develop amblyopia.