Retrieved from: 2016-02-01 Concord Eye News In China, 80% – 90% of high school students suffer from myopia, and about 20% are highly myopic, and this value is still increasing. This is a huge burden not only to individuals but also to the society. Early onset myopia is more likely to develop into high myopia, with a range of serious complications such as macular degeneration, leading to irreversible damage to vision. There is currently no effective way to prevent myopia from occurring, and existing methods to control myopia progression, such as corrective eyeglasses and atropine, are not effective. Prof. Mingguang He and his team have shown that increasing the amount of time spent outdoors can prevent myopia, and the results were published in the journal JAMA. The study was a cluster randomized trial of 1,903 first-grade students from 12 elementary school in Guangzhou, China, from October 2010 to October 2013, who were randomly divided into an experimental group (952 students from 6 schools) and a control group (951 students from 6 schools). There were no statistically significant differences in the sex ratio, myopia incidence, and axial length between the experimental and control groups at baseline. Students in the experimental group were given an additional 40 minutes of extracurricular activities per day on top of their normal routine and their parents were encouraged to participate in more outdoor activities during vacations, while the control group followed their normal routine. The study was followed up for 3 years, with ciliary muscle palsy optometry, eye axis length, and corneal curvature measurements taken annually in the study population. Observations were made on the cumulative incidence of myopia over the 3 years as well as on the values of change in equivalent spherical lens degrees and ocular axis length. Baseline Level Characteristics of the Study Population The mean age of the children in the experimental and control groups was 6.6 years. The 3-year cumulative prevalence of myopia was 30.4% in the experimental group and 39.5% in the control group, which was statistically different.The 3-year equivalent spherical lenticule change was -1.42 D in the experimental group and -1.59 D in the control group, which was statistically significant. Axial length change was 0.95 mm in the experimental group and 0.98 mm in the control group, with no statistical difference between the two groups. 3-year follow-up refractive as well as biological findings Increasing the time spent outdoors reduces the incidence of myopia. Two previous studies with smaller sample sizes and shorter follow-up periods have reached similar conclusions that increasing time spent outdoors has a protective effect against myopia. Interestingly, this protective effect was positively correlated with the amount of time spent outdoors, but not with the amount of time spent in physical activity, and indoor physical activity did not reduce the incidence of myopia, a mechanism that needs to be further investigated. Winter vacation is here, open the door, take the children to the outdoors to reduce the burden on the eyes. (All tables in the text are from the original article.) Original: Effect of Time Spent Outdoors at School on the Development of Myopia among Children in China a Randomized Clinical Trial. Mingguang He, MD, PhD; Fan Xiang, PhD. Mingguang He, MD, PhD; Fan Xiang, MD, PhD; Yangfa Zeng, MD; Jincheng Mai, BSc; Qianyun Chen, MSc; Jian Zhang, MSc; Wayne Smith, MD, PhD; Kathryn Rose, PhD; Ian G. Morgan, PhD. PhD . JAMA. 2015;314(11):1142-1148. doi:10.1001/jama.2015.10803. SHORT COMMENTARY: Currently, the occurrence of myopia in China is getting younger and younger, and the early onset of myopia is prone to develop into high myopia. There are many scholars devoted to study how to delay the progression of myopia, such as keratoplasty lenses and topical use of atropine eye drops, which have some efficacy. However, increasing outdoor time is undoubtedly a highly recommended method to prevent myopia in non-myopic children. This article by Prof. Ho used a randomized study with a large sample and a follow-up period of 3 years to confirm that increasing outdoor time can effectively reduce the incidence of myopia. When counting the daily outdoor time, the authors used weekend outdoor time to estimate the outdoor time of students during summer and winter vacations. Because most of the parents in China are both working parents, in fact, they have little time to accompany their children during the holidays, resulting in some children in turn spending less time outdoors than the usual weekend time, and some scholars are now aware of this problem and are calling on parents to pay attention to protecting their children’s vision during the holidays. As far as this paper is concerned, if this situation is taken into account, the difference between the test group and the control group may be even greater. –Dongdong Xu