Hyperopia and neovascularization in age-related macular degeneration.

Refractive errors for phakic eyes of patients referred with age-related macular degeneration were reviewed to determine whether some range of refractive error might be a risk factor for the neovascular form. The authors compared refractive errors of 198 patients with unilateral neovascular disease with refractive errors of 129 patients with bilateral dry disease. These groups had comparable distributions with respect to age, sex, and visual acuity of their better eyes. Student's t tests and multiple linear regression analyses were performed to assess group differences in mean refractive error. Contingency table and multiple logistic regression analyses were performed to determine odds ratios for having the neovascular form based on a stratification of refractive error. By comparing better eyes of the two groups, patients with the unilateral neovascular form had an average spherical equivalent that was 1.0 diopter (D) more hyperopic than that of patients with the bilateral dry form (P < 0.001). Patients with a refractive error of +0.75 D or greater were more likely to have the neovascular form compared with patients with other refractive errors (odds ratio, 2.40; 95% confidence interval, 1.53-3.78; P < 0.001). Similar relationships between the two groups of patients were found by comparing worse eyes. These findings suggest that hyperopia is a risk factor for choroidal neovascularization among patients referred with age-related macular degeneration.