Illuminating Risk: An Ecological Analysis of Artificial Light at Night and Childhood Myopia Using State-Level US Data.

PURPOSE: Childhood myopia is a growing global health concern, associated with serious vision complications later in life, including retinal detachment and myopic macular degeneration. While behavioral factors such as screen time and reduced outdoor exposure have been studied, the potential contribution of environmental light pollution, particularly artificial light at night (ALAN), remains underexplored at the population level. METHODS: We analyzed 2019 data from 46 US states to examine the association between ALAN and the prevalence of childhood myopia (ages 0-17). VIIRS satellite-derived nighttime radiance was used as a proxy for outdoor ambient lighting. Using generalized additive modeling (GAM), we examined nonlinear associations while adjusting for behavioral (screen time, insufficient sleep) and structural (Medicaid coverage, uninsured children, vision screening, optometrist density, urbanization) factors. Multicollinearity was assessed using Spearman correlation and variance inflation factors. RESULTS: The final GAM explained 65.3% of the deviance in childhood myopia prevalence (adjusted R2 = 0.509). Higher ALAN was significantly associated with higher myopia prevalence (F = 8.39, p = 0.0068). Screen time showed a nonlinear relationship, whereas sleep deprivation showed an unexpected inverse association, potentially reflecting detection disparities. Medicaid coverage showed a U-shaped association, with both low and high coverage associated with higher prevalence. Vision screening rates were positively associated with myopia prevalence, likely reflecting improved detection. Urbanization, optometrist density, and the number of Asian children were not statistically significant. CONCLUSION: ALAN is a population-level correlate of childhood myopia in the US. Although not indicative of individual-level risk, its association warrants further ecological investigation and may merit consideration in environmental health and urban planning discussions. These findings highlight the multifactorial nature of pediatric refractive error and the value of integrating environmental exposure data into public health vision surveillance. Further individual-level research is needed to assess causal mechanisms.