Ozone Exposure and Myopia in Schoolchildren: A Nationwide Multicenter Cross-Sectional Study in China

Abstract

Environmentally-induced myopia have markedly increased worldwide, but the direct correlation between ozone (O3) exposure and myopia remains limited in existing research. To clarify the association between ambient O3 exposure and childhood myopia, analyze the mediating role of intraocular pressure (IOP) in axial length (AL) elongation, and further investigate the effect modification by fine particulate matter (PM2.5) and average temperature (Tavg) in these associations, we conducted this national multi-center cross-sectional study among 35,844 students from 34 schools in 19 Chinese cities. All participants underwent ophthalmic examinations, including uncorrected visual acuity (UCVA), spherical equivalent (SE), IOP, AL, and corneal curvature (KRT). Ambient exposure data were obtained from the Chinese Air Quality Online Monitoring and Analysis Platform. Logistic regression models were used to assess the association between O3 and myopia, with effect modification by PM2.5 and Tavg. Mediation analysis was conducted to explore the mediating role of IOP in the O3 -AL association. There were 35,844 participants with a mean age of 7.7 ± 1.2 years, with 41.7% being myopic. For each 1 μg/m3 increase in O3, the OR of myopia prevalence was 1.003 (95% CI: 1.002, 1.005), and the SE decreased by 2.215 × 10–3 D (95% CI: -3.180 × 10–3 D, -1.249 × 10–3 D), AL increased by 0.831 × 10–3 mm (95% CI: 0.191 × 10–3 mm, 1.471 × 10–3 mm), and IOP increased by 0.021 mmHg (95% CI: 0.018 mmHg, 0.024 mmHg). And O3 may contribute to AL elongation by increasing IOP (mediation proportion: 2.16%, P = 0.038). In addition, PM2.5 and Tavg modify the association between O3 and myopia. In conclusion, ambient O3 exposure is associated with increased myopia risk, reduced SE, AL elongation, and elevated IOP in children. PM2.5 and Tavg modify these associations, while IOP partially mediates the O3–AL relationship.