Effects of myopia on health-related quality of life in adolescents: a population-based cross-sectional causal empirical survey.

Objective: Myopia is a prevalent disease affecting adolescent vision and harms various health outcomes. However, the evidence about the effects of myopia on adolescents' overall health status is limited. Using health-related quality of life (HRQoL), a comprehensive health measurement indicator, this study aims to evaluate the effects of myopia on adolescents' HRQoL.

Methods and analysis: Adolescents' HRQoL was measured by the Child Health Utility 9D instrument. Data were collected from a population-based cross-sectional survey conducted in Shandong province of China. To mitigate the potential endogeneity bias, parents' myopia degree was used as the instrumental variable for adolescents' myopia status. The causal model was built to explore the effects and potential mediators of myopia on the HRQoL of adolescents. Heterogeneity analysis was used to identify susceptible groups.

Results: 108 657 adolescents with an average age of 12 were included in the analysis. Compared with adolescents without myopia, the health utility value of individuals with low, moderate and high decreases by 0.5%, 1.1% and 2.2%, respectively. The reduction of outdoor activity time and increase in electronic device usage time play the mediator role. Myopia leads to a greater decrease in the health utility value of adolescents in higher grades, boarding schools and low-income households compared with their counterparts.

Conclusion: Myopia impairs adolescents' HRQoL and damages the overall health level of adolescents. The frequency of outdoor activity and electronic device usage could be the potential mediators. The susceptibility of adolescents in higher grades, boarding schools and low-income households would be exacerbated.