A longitudinal study of the effect of ocular biometrics measures on myopia onset.

PURPOSE:To investigate the relationship between ocular biometrics (OB) and myopia onset. METHODS:OB data from students in 4 grades (aged from 6 to 14 years) in China were collected in a 1.5-year longitudinal study. Refractive error was assessed with cycloplegic autorefraction. RESULTS:At baseline, 934 (56.33%) of the subjects (right eye) had myopia. The mean spherical equivalent (SE) and axial length to corneal radius (AL/CR) were - 2.14 ± 1.49 and 3.14 ± 0.11, respectively, in the subjects with myopia and - 0.09 ± 0.21 and 2.98 ± 0.07, respectively, in the subjects without myopia. The correlation between the SE and AL/CR was r = - 0.823 (P < 0.001). The slopes of the SE changing with the AL/CR (and R-squares) were - 0.28 to - 1.80 (0.01-0.14) in the no myopia group, - 3.40 to - 6.20 (0.20-0.48) in the low myopia group, and - 3.37 to - 11.34 (0.16-0.74) in the moderate and high myopia groups. The baseline AL/CR values in grades 1, 3, and 5 were higher in those who developed myopia within 1.5 years. The odds ratio of the AL/CR to myopia onset in 1.5 years was 1.096 (95% confidence interval (CI): 1.060-1.135). CONCLUSIONS:Of the five indicators, the AL/CR showed the best correlation with the SE. The adjoint and linear relationship between the AL/CR and the SE tended to increase with SE progression. When myopia progressed beyond a certain range, the AL/CR was significantly different in those without initial myopia who developed it within 1.5 years compared with those who did not. After adjusting for age, sex, school, and grade, the interpretation capability of the current AL/CR to myopia onset in 1.5 years was limited.