Researchers are unsure of the long-term effects, but the onset of myopia was at least delayed in children who spent more time outside during the study. Photo by Alinute Silzeviciute/Shutterstock
GUANGZHOU, China, Sept. 15 (UPI) -- As little as 40 minutes a day playing in the sun can help hold off the development of myopia, or nearsightedness, in children, according to a large study of children in China.
About 30 percent of the United States population is affected by myopia, which is the inability to properly focus on distant objects without eyewear or surgery, according to the National Health and Nutrition Examination Survey. Among schoolchildren, about 6 percent have myopia, though the number of children with it generally increases over time.
"Both schools and parents should encourage students to spend more time outdoors so long as the UV protection measures are undertaken," Dr. Mingguang He, of Sun Yat-sen University, told CBS News. "Schools, if they can't add more outdoor classes in the curriculum, should at least bring the students outside during school recess. Parents should encourage or bring their children outside on the weekends, in particular children at high risk developing myopia, for example, children who have parents who are both myopic."
The researchers worked with 1,900 6-year-old schoolchildren at 12 schools in Guangzhou between 2010 and 2013. At six of the schools, administrators added 40 minutes of outdoor play to the school day and parents were encouraged to engage in outside activities with their children on the weekend. The other six schools did not add outdoor periods to the day and parents maintained their normal routines.
Among the 952 children at the six test schools, 30.4 percent developed myopia during the three-year study, while 39.5 percent of children at the other schools developed the condition, researchers reported in the study, published in the Journal of the American Medical Association.
Researchers said the 9.1 percent difference between the two groups of children signaled a 23 percent reduction in myopia, which was actually less than expected. They note that small children who develop myopia have a quicker progression than older children, but that the extra outdoor activity could have long-term benefits.
The prevalence of myopia is an important healthcare concern, even though refractive correction is so successful," wrote Dr. Michael Repka, of the Johns Hopkins University School of Medicine, in a commentary published alongside the study. "Patients with myopia report a lower quality of life, especially those with higher degrees of myopia."