Prevalence and Associations of Myopic Anisometropia in Chinese Adults

Purpose: To investigate the prevalence and associations of myopic anisometropia in Chinese adults. Methods: A total of 3,791 Chinese refractive surgery candidates with myopia (25.15 +/- 7.09 years old, Mean +/- SD) were recruited. All eyes underwent a standardized ophthalmological examination. Associations between myopic anisometropia and age, gender, spherical ametropia, astigmatism, and axial length (AL) were analyzed by means of the chi-squared test, nonparametric Kruskal-Wallis or Mann-Whitney test, binomial logistic regression analyses, and multivariate logistic regression analysis. Results: The mean myopic anisometropic level was 0.96 D and prevalence of myopic anisometropia was 29.62% (defined as myopic anisometropia >= 1.00 D). The prevalence and severity of myopic anisometropia increased with age, larger interocular AL difference, and higher cylindrical power (all P<0.001). Myopic anisometropia showed a U-shaped correlation with spherical equivalent (SE) refractive error and V-shaped correlations with AL, J0 and J45. Myopic anisometropia was most strongly associated with interocular AL difference (P<0.001). Conclusions: Compared with previous reports, this study revealed an even higher prevalence of myopic anisometropia and showed a U-shaped correlation with SE and a V-shaped correlation with AL. These results indicate that the formation of myopic anisometropia could be related to neural control in the binocular AL growth balance. Further study is needed to clarify this presumption.