Outdoor artificial light at night exposure and risk of myopia: A cross-sectional and prospective cohort study among Hong Kong children

BACKGROUND: Outdoor artificial light at night (ALAN) has emerged as a significant source of environmental pollution. However, epidemiological evidence on its impact on childhood myopia development remains limited. Therefore, this study aims to investigate the association between outdoor ALAN exposure and myopia development. METHODS: /sr) within 500 m of each residence was estimated using time-varying satellite data. Myopia was defined as cycloplegic spherical equivalent refraction ≤ -0.50 diopters. Associations were estimated using multivariable logistic regression and time-varying Cox proportional hazards models, adjusting for demographic (age and sex), behavioral (e.g., near-work and outdoor time), parental myopia, and socioeconomic (e.g., family income) factors. Restricted cubic splines were employed to explore exposure-response relationships. RESULTS: /sr. Further subgroup analysis revealed that older children (≥ 7.35 years) were more vulnerable to outdoor ALAN-associated incident myopia (HR, 1.27; 95% CI, 1.17-1.39; P for interaction < 0.001) compared to younger children (< 7.35 years). CONCLUSION: Outdoor ALAN exposure is positively associated with childhood myopia development. Given the observational design and limited understanding of mechanisms, further replication and mechanistic studies are warranted to confirm these findings to help inform future public health policies for myopia prevention.