For kids in school, going outside to play for an extra 40 minutes a day might reduce the risk of nearsightedness, according to a new study.
Researchers behind the study, which was published Tuesday in the Journal of the American Medical Association (JAMA), conducted a randomized trial in order to assess the efficacy of myopia prevention through increased time outdoors for school children.
Myopia — which is caused by an eye defect, often a misshapen lens or elongated eyeball — results in an inability to clearly distinguish distant objects. In other words, objects at a distance appear blurred while objects up close can be seen clearly.
Analyzing nearly 2,000 first-graders in China, the researchers found that after three years, those who spent more time playing outdoors were 23 percent less likely to develop myopia.
The group of kids who spent more time outdoors, those less apt to develop shortsightedness, were tasked with an extra 40 minutes of outdoor activity time after school each day and their parents were encouraged to get them to play outdoors over the weekends.
Dr. Mingguang He of Sun Yat-sen University in Guangzhou, China, the study’s lead author, was quoted by CBC as having said that the new study “is able to prove causality and also provide the high level of evidence to inform public policy.”
There were some studies suggesting the protective effect of outdoor time in the development of myopia, but most of this evidence is from cross-sectional studies (survey) data that suggest ‘association’ instead of causality (…) Our study, as a randomized trial, is able to prove causality and also provide the high level of evidence to inform public policy.
While the study’s findings are clear, its authors note that further studies are necessary in order to assess the generalizability of its findings.
