Physical activity for the co-prevention of myopia and obesity in children and adolescents: a scoping review.

Introduction: Myopia and obesity have become two of the most prevalent public health challenges among children and adolescents, often co-occurring in the same demographic groups. Traditional prevention strategies typically address these conditions separately, failing to consider their shared lifestyle determinants and potential comorbidity mechanisms. This scoping review aims to examine the role of physical activity and outdoor exposure in the joint prevention of myopia and obesity, synthesizing existing evidence and exploring their associations with comorbidity patterns, potential mechanisms, and integrated prevention frameworks. Methods: We systematically searched PubMed, Web of Science, and China National Knowledge Infrastructure for observational and interventional studies that concurrently examined physical activity and/or outdoor exposure in relation to myopia- and obesity-related outcomes. We applied a scoping review approach to chart and thematically synthesize the evidence, without conducting a quantitative meta-analysis. Results: Thirteen studies were included in the analysis. The findings consistently show that myopia-obesity comorbidity is prevalent and increasing among children and adolescents. Insufficient physical activity and reduced outdoor exposure were associated with higher obesity risk and poorer visual outcomes. Longitudinal evidence suggests that outdoor activity not only reduces myopia risk but also modifies the relationship between obesity and myopia. National cohort data indicate that suboptimal school physical activity environments are linked to higher myopia-obesity comorbidity risk. Additionally, cohort studies suggest a bidirectional relationship, with early visual problems predicting subsequent increases in BMI. Conclusion: Physical activity and outdoor exposure may be key modifiable targets for co-preventing myopia and obesity. The school physical activity environment is particularly significant as a structural determinant in integrated prevention efforts. This review proposes a school-based co-prevention framework that focuses on physical activity as a central behavioral nexus, and further studies are needed to test and strengthen this approach with longitudinal and intervention research.