Purpose: To describe the association between refractive errors, ocular biometry, and age-related macular degeneration (AMD) in an Asian Malay population in Singapore.
Methods: A population-based study of 3280 Malay individuals aged 40 to 80 years was conducted in Singapore. Early- and late-AMD signs were graded from retinal photographs according to the Wisconsin grading system. Autorefraction, followed by subjective refraction, was performed to obtain spherical equivalent refraction (SER) in diopters, with emmetropia defined as SER -0.5 to +0.5 D, hyperopia as > +0.5 D, and myopia as < -0.5 D. Partial coherence laser interferometry was used to measure axial length, anterior chamber depth, and corneal curvature. The association between refractive status, ocular biometry and the prevalence of both early and late AMD were analyzed.
Results: Hyperopic refractive error (odds ratio [OR] 1.54; 95% confidence interval [CI] 1.00-2.36; compared with myopia, P = 0.05), shorter axial length (OR, 1.91; CI, 1.05-3.46, comparing 1st vs. 4th quartiles; P = 0.03), and steeper corneal curvature (OR, 1.93; CI, 1.16-3.20, comparing 1st vs. 4th quartiles, P = 0.01) were significantly associated with early AMD, after adjustment for age, sex, smoking, education, height, and systolic blood pressure. Each diopter increase in hyperopic refraction and each millimeter decrease in axial length was associated with an 8% (OR, 1.08; CI, 1.01-1.16; P = 0.03) and 29% (OR, 1.29; CI, 1.06-1.57; P = 0.01) increased risk of early AMD, respectively. No significant association was noted of refractive error and ocular biometry with late AMD.
Conclusions: Hyperopic refractive error and shorter axial length are associated with early AMD in Asian eyes.