Longitudinal Changes in Axial Length and Spherical Equivalent in Children and Adolescents With High Myopia

Purpose: To investigate longitudinal changes in axial length (AL) and spherical equivalent (SE) in children and adolescents with high myopia and to explore associated risk factors.Methods: This was a longitudinal, observational cohort study of highly myopic participants (aged 7-17 years) to evaluate the mean rates of change in AL and SE. Mixed effects regression models were used to explore the risk factors.Results: The sample consisted of 293 participants (mean age at the baseline, 13.63 +/- 2.66 years; mean AL, 27.03 +/- 1.30 mm diopters; mean SE, -8.99 +/- 2.30 diopters) who were followed for 7.09 +/- 1.64 years. Pathological myopia (PM) was present in 11.95% of the participants at the baseline. Over the follow-up period, the mean AL and SE progression rates were 0.13 mm/y (95% CI, 0.12-0.14) and -0.36 diopters/y (95% CI, -0.39 to -0.34). The multivariate analysis showed that the AL elongation and myopic SE progression decreased significantly after age 11 (beta = -0.080, P < 0.001; beta = 0.146, P < 0.001), increased with a greater baseline SE (beta = -0.006, P = 0.014; beta = 0.017, P = 0.005), and accelerated in children and adolescents who had PM at the baseline (beta = 0.043, P = 0.011; beta = -0.097, P = 0.025).Conclusions: A significant association was found between acceleration of AL elongation and myopic SE progression among the children and adolescents with age, especially those younger than 11 years, and the presence of PM.