Abstract
The prevalence of visual impairment (VI) increases with axial length (AL) and spherical equivalent (SE). This study aims to explore the prevalence and associated factors of myopia and AL-related VI in children and adolescents, including analysis of sex-specific differences. This cross-sectional survey included 2595 children and adolescents aged 4-18 years from nine educational institutions in a large municipality. The survey comprised a questionnaire, visual acuity examination, refractive screening and AL measurement. The prevalence of myopia and AL-related VI were 56.53% and 50.98% respectively and increased with age (P < 0.01). The myopia rate was higher in females than in males (60.23% vs. 52.71%, χ(2) = 14.93, P < 0.05), with a significant difference observed in those aged 9 years and older. However, there was no sex difference between in the prevalence of AL-related VI (51.37% vs. 50.61%, χ(2) = 0.15, P = 0.70). The research showed that older adolescent was a risk factor for both myopia (OR = 2.28, 95%CI = 2.06-2.53) and AL-related VI (OR = 2.49, 95%CI = 2.23-2.77). Having a myopic parent was also significantly associated with myopia (OR = 1.21, 95%CI = 1.12-1.32) and AL-related VI (OR = 1.25, 95%CI = 1.16-1.36). The prevalence of myopia and AL-related VI were high and increased with age in children and adolescents, with sex-specific differences in myopia but not in AL-related VI. Therefore, it is possible to predict the risk of myopia by considering age- and sex-specific factors.