Ocular biometrics as a function of age, gender, height, weight, and its association with spherical equivalent in...

To determine the distribution of ocular biometric components, including axial length, lens thickness, and vitreous chamber depth, their relationship with personal characteristics, and spherical equivalent refraction after adjusting axial length and vitreous chamber depth for personal characteristics.

Among 6- to 12-year-old children, urban subjects were selected using random cluster sampling, and in rural areas, all eligible subjects were considered for enrollment. Ocular biometrics were measured using BioGraph. Data were summarized as mean and 95% confidence intervals. Linear regression was used to investigate the relationships between the study variables.

Data from 4938 children were analyzed. Mean axial length, lens thickness, and vitreous chamber depth were 23.02 (95% confidence interval: 22.97-23.07) mm, 3.48 (95% confidence interval: 3.47-3.49) mm, and 20.63 (95% confidence interval: 20.59-20.66) mm, respectively. According to the multiple linear regression model, axial length and vitreous chamber depth associated positively with height (β = 0.020, P < 0.001; β = 0.018, P < 0.001, respectively) and inversely with female gender (β = -0.522, P < 0.001; β = -0.386, P < 0.001, respectively). Also lens thickness correlated inversely with age (β = -0.019, P < 0.001) and positively with female gender (β = 0.043, P < 0.001). After adjusting for personal characteristic, spherical equivalent had an inverse relationship with axial length (β = -0.441, P < 0.001) and a positive relationship with lens thickness (β = 0.423, P < 0.001). Among the studied variables, axial length had the strongest association with spherical equivalent (standardized coefficient: -0.39).

This cross-sectional study showed a general pattern of ocular biometric components. The axial length value was almost similar to European countries, but less than that in the Eastern and Southeast Asian populations. By increasing age, axial length and vitreous chamber depth increased while lens thickness and spherical equivalent decreased. Among all ocular biometric components, axial length was strongest determinant for spherical equivalent.