Outdoor Artificial Light Exposure Linked to Increased Odds of Myopia

The researchers suggested that this heightened susceptibility in older children may be driven by age-related behavioral differences. For example, older children may have increased academic burdens and later bedtimes, extending their duration of exposure to artificial light at night before sleep. Photo: Daniel Akselrod/Unsplash. Click image to enlarge. Adequate outdoor time, proper indoor lighting and good sleep habits are among the recommendations given for a myopia mitigation strategy. Less is known about the influence of outdoor lighting. With rapid urbanization, outdoor artificial light has emerged as a new and pervasive environmental hazard in modern societies, shifting the research focus from indoors to outdoors. Researchers in Hong Kong recently investigated the association between outdoor artificial light at night and myopia development, and found positive associations that argue for some form of linkage.“These findings suggest that excessive outdoor artificial light at night may contribute to childhood myopia development, and that mitigating such exposure could benefit children's refractive development,” the study authors wrote in their paper, which was published in Environmental Research.This cross-sectional and prospective cohort study included children from the Hong Kong Children Eye Study, a population-based cohort with a three-year follow-up. Outdoor artificial light at night exposure within 500 meters of each residence was estimated using satellite data and broken into four groups based on intensity. Myopia was defined as cycloplegic spherical equivalent refraction ≤ -0.50D. A total of 19,114 children (mean age 7.4; 52.8% boys) were included at baseline, with 2,558 non-myopic children completing the prospective follow-up.In statistical models, each increase in outdoor artificial light intensity among the four categories was associated with an 8% higher risk of myopia prevalence (odds ratio: 1.08) and a 26% higher risk of myopia incidence (hazard risk: 1.26). The researchers noted a nonlinear relationship with myopia incidence, however. Older children (≥7.35 years) were more vulnerable to outdoor artificial light–associated incident myopia (HR: 1.27) compared with younger children.“The absence of significant modification effects by other factors such as parental myopia and family income may suggest that outdoor artificial light at night acts as an independent environmental risk factor, regardless of the predisposition and socioeconomic status,” the researchers wrote. “Although this type of light exerts widespread effects, the findings in the subgroup analyses highlight that children with both parental myopia and those from lower-income families faced a higher burden of developing myopia.”They did emphasize that given the observational design, reliance on satellite-derived metrics, potential residual confounding and limited understanding of mechanisms, these findings should be interpreted cautiously, especially regarding causal inference.The study concluded that further longitudinal investigations incorporating objective individual light monitoring and rigorous experimental studies are warranted to confirm our findings and elucidate the underlying pathways, which may help to inform future public health policy for myopia prevention.Click here for the journal source. Li Y, Zhang Y, Kam KW, et al. Outdoor artificial light at night exposure and risk of myopia: a cross-sectional and prospective cohort study among Hong Kong children. Environ Res. 2026;303(Pt 1):124647. This article was developed by the editorial staff in conjunction with experts in the field. In the process, AI may have been among the editorial tools used to meet the goals of human editors, who approved all content.