Outdoor artificial nighttime light may raise childhood myopia risk

Higher exposure was associated with new-onset myopia over 3 years, with risk increasing sharply at higher nighttime light levels.

To investigate the association between outdoor artificial light at night (ALAN) exposure and the risk of developing myopia in children.

Study Design: Cross-sectional and prospective analyses using data from the Hong Kong Children Eye Study, involving 19,114 children with a mean age of 7.4 years.
Data Collection: Outdoor ALAN exposure was estimated from satellite data within 500 m of each participant's residence.
Myopia Definition: Myopia was defined as cycloplegic spherical equivalent refraction of −0.50 diopters or less in either eye.
Statistical Analysis: Models accounted for various factors including age, sex, body mass index, parental myopia, and environmental exposures.

The relationship between outdoor ALAN and incident myopia was nonlinear, with an inflection point at 93.08 nW/cm²/sr indicating increased risk.

Findings should be interpreted cautiously regarding causal inference; further longitudinal studies are needed to clarify potential mechanisms.