Could outdoor activities protect children from myopia? : a literature review

Abstract

Background: Over the last fifty years, the prevalence of myopia in children, adolescents and young adults (defined here as person up to 25 years old) dramatically rises throughout the world, especially in East Asia, such as China, Singapore, South Korea, Japan as well as Taiwan. For the sake of finding the cause and prevention of the epidemic of myopia, the environmental factor –time spent outdoors seems potentially beneficial to against epidemic myopia. Therefore, recently, more and more studies focus on the evidence of its potential protective effect on myopia.

Objective: Summarizing and assessing the evidence of whether outdoor activities could protect children, adolescents and young adults from myopia, and establishing further purposes of later studies, especially for clinical trials

Methods: Relevant observational studies were identified by searching on the online database, PubMed and Web of Science. The evidence of protective effect was extracted and summarized. All the included studies were assessed by Newcastle-Ottawa Scale (NOS) quality assessment.

Results: Sixteen observational studies included (5 cohort and 11 cross-sectional studies). The most of the studies concluded that outdoor activities consistently inversely assiocated with myopia development.

Conclusion: In this review, most of observational studies provided epidemiological and statistical evidence on the protective effect of time outdoors to the development of myopia. Therefore, this association is consistent and robust. However, we should also focus on the effect of the progression of myopia as well, which is still unclear and the result varies and inconsistent. The further studies are required to establish, such as interventional studies and find the association between progression of myopia and outdoor activities.