Longitudinal association of multi-dimensional nighttime light characteristics on myopic shift

Background Nighttime light exposure may disrupt the circadian rhythm by affecting chronotypes, thereby influencing myopia, with chronotype-related genes potentially driving individual variations in sensitivity to light. Utilizing wearable devices to objectively monitor personal light exposure, the present study explores the associations between multidimensional nighttime light metrics and myopic shift. Furthermore, we construct an evening chronotypes polygenic risk score (PRS) to evaluate the interrelationship.Methods This nested within the Ma'anshan Birth Cohort utilized light meters to monitor personal nighttime light exposure of 535 individuals for seven consecutive days. Four-dimensional optical indicators, including rhythm stability, fluctuation, specific intensity light duration in key time windows, and cumulative exposure were constructed. Ophthalmic examinations were conducted in 2022 and 2026. An evening PRS was constructed using single nucleotide polymorphisms identified through genome-wide association studies. We evaluated the independent and interactive associations of nighttime light exposure characteristics and evening PRS with myopic shift.Results High-intensity light during the mid-sleep (β = -0.81; 95% CI: -1.33, -0.28), full-sleep (β = -0.38; 95% CI: -0.69, -0.07), high-intensity light pulses (β = -0.17; 95% CI: -0.33, -0.01), and evening PRS (Moderate: β = -0.32; 95% CI: -0.55, -0.09; High: β = -0.33; 95% CI: -0.55, -0.11) were associated with an increased risk of myopic shift. No associations were observed for mixed cumulative exposure across different time windows. No stable interaction was observed between the evening PRS and nighttime light exposure features. These exploratory findings were verified by multiple methodological and sensitivity analyses.Conclusions This exploratory study is the first to investigate the associations of nighttime light stimulation and evening PRS with myopic shift. These findings underscore the vital importance of maintaining a dark nighttime environment for the prevention and control of childhood myopia.