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Meta-analysis confirms time outdoors may prevent myopia
A systematic review followed by meta-analysis and dose-responsive analysis provided evidence of the protective effect of time spent outdoors for preventing myopia in children.
The same protective effect was not found on myopic progression in children who were already myopic.
Researchers searched relevant publications in PubMed, EMBASE and the Cochrane Library, and 604 articles were identified. Of these, 25 met the study criteria.
With respect to geographic location, East Asia prevailed, with 17 studies conducted in China, Taiwan and Singapore. The remaining studies were from Australia, the U.K., the U.S. and Turkey. Participants were mostly schoolchildren between 6 and 18 years old.
A linear correlation was found between increased time spent outdoors and the risk of myopia onset, with a 50% reduction of incident myopia when the increase was approximately 76 minutes per day. In all studies, including those that failed to demonstrate a protective effect, myopic children spent, on average, less time outdoors compared with those without myopia.
Subgroup analysis indicated a stronger protective effect in children 6 years of age as compared with older groups.
As the authors noted, the ocular component undergoes maturation at this age and might be more sensitive to environmental factors.
“Further research is required to confirm and determine the reasons for outdoor time not being effective for myopic progression; and there is a need to determine the optimal duration and strategy to implement outdoor time as an intervention to control or delay the onset of myopia,” the authors concluded. – by Michela Cimberle
Disclosure: None of the authors reports relevant disclosures