40 Minutes of Outdoor Activity per Day May Slow Epidemic of Myopia in Children

Thursday, October 1 2015 | 00 h 00 min | Vision Science

Myopia has reached epidemic levels in some countries in east and south-east Asia, where 80-90% of children will develop myopia by the time they graduate from high school. A new study published in the September 15 issue of the Journal of the American Medical Association (JAMA) offers evidence that an additional outdoor activity class resulted in a 9.1% reduction in the incidence rate of myopia, and a significantly lower cumulative change in spherical equivalent refraction (SER) over a period of three years.

The study divided grade 1 students in Guangzhou, China, into two groups of approximately 950 students each (average student age 6.6 years). One group had an additional class of 40 minutes of outdoor activities each day, while the other group continued their usual activity pattern.

The study found that overall there was a 23% relative reduction in myopia incidence, which was less than the reduction anticipated by the study leaders, but clinically significant because delaying myopia onset in childhood can reduce the likelihood of progression to severe myopia later in life.

Michael Repka, M.D., of the Johns Hopkins University School of Medicine, said of the findings: “Given the popular appeal of increased outdoor activities to improve the health of school-aged children in general, the potential benefit of slowing myopia development and progression by those same activities is difficult to ignore. Although prescribing this approach with the intent of helping to prevent myopia would appear to have no risk, parents should understand that the magnitude of the effect is likely to be small and the durability is uncertain.”

Further information: http://jama.jamanetwork.com/article.aspx?articleid=2441261