After implementing a new initiative to promote increased time outdoors to stave off myopia progression, researchers found that the policy was successful in reversing the long-term trend of increased low visual acuity (VA) in Taiwanese schoolchildren.
This prospective cohort study evaluated data from the Taiwan School Student Visual Acuity Screen (TSVAS), which required each school in Taiwan to measure uncorrected VA (UCVA) in students in grades one through six every half year from 2001 to 2015. UCVA of 20/25 or less was considered reduced VA.
From 2001 to 2011, the team discovered that the prevalence of reduced VA in schoolchildren increased from 34.8% to 50.0%. After instituting a program in September 2010 that encouraged schools to take students outdoors for 120 minutes every day for myopia prevention, they noted that the prevalence decreased from 49.4% in 2012 to 46.1% in 2015. Controlling by gender and grade, they observed a significant constant upward trend in the mean annual change in prevalence before the intervention and a constant decrease of -2.34% annually after.
“Since the efficacy of increased time outdoors in slowing the onset of myopia has been demonstrated in randomized trials, interventions to promote increased time outdoors may be useful in other areas affected by an epidemic of myopia,” the study authors concluded in their paper.
|Wu PC, Chen CT, Chang LC, et al. Increased time outdoors is followed by reversal of the long-term trend to reduced visual acuity in Taiwan primary school students. Ophthalmology. February 7, 2020. [Epub ahead of print].