Association between Refractive Errors and Ocular Biometry in an Elderly Population.

Abstract

The anterior chamber depth in hyperopic eyes is significantly deeper than that in myopic eyes, and this finding is independent of the axial length. This study aimed to determine the relationship between and refractive errors and ocular biometric components in a geriatric population 60 years and older. The present population-based cross-sectional study was performed using a multistage random cluster sampling method in Tehran, Iran. After selecting the samples, visual acuity measurement, autorefraction, subjective refraction, and slit-lamp examination were performed for all participants. Ocular biometric indices were measured with Pentacam AXL (Oculus, Wetzlar, Germany). The correlation coefficients of spherical equivalent with axial length, corneal radius of curvature, axial length/corneal radius of curvature ratio, and anterior chamber depth were -0.40, 0.14, -0.63, and -0.18, respectively, after controlling the effects of age, sex, and nuclear cataract. The axial length (24.84 vs. 21.21 mm), the anterior chamber depth (2.74 vs. 2.34 mm), the ratio of the axial length to the corneal radius of curvature (3.35 vs. 2.71), and the anterior chamber volume (138.59 and 105.54 mm 3 ) were the highest and lowest in myopic and hyperopic individuals, respectively (all P < .001). In the first model, axial length and nuclear cataract were significantly inversely related to the spherical equivalent. However, corneal radius of curvature, anterior chamber depth, central corneal thickness, and corneal diameter had a significant direct relationship with the spherical equivalent. In the second model, the axial length/corneal radius of curvature ratio and cataract showed an inverse relationship with the spherical equivalent, whereas anterior chamber depth and corneal diameter had a direct relationship with the spherical equivalent. Among the biometric components, the axial length/corneal radius of curvature ratio has the strongest relationship with refractive errors. The anterior chamber depth is lower in myopes compared with hyperopes after controlling the effect of axial length.