title: Effect of outdoor activity on myopia onset and progression in school-aged children in northeast China: the Sujiatun Eye Care Study.
abstract: BACKGROUND
  Due to its high prevalence and associated sight-threatening pathologies, myopia has emerged as a major health issue in East Asia. The purpose was to test the impact on myopia development of a school-based intervention program aimed at increasing the time student spent outdoors.
  
  
  METHODS
  A total of 3051 students of two primary (grades 1-5, aged 6-11) and two junior high schools (grades 7-8, aged 12-14) in both urban and rural Northeast China were enrolled. The intervention group (n = 1735) unlike the control group (n = 1316) was allowed two additional 20-min recess programs outside the classroom. A detailed questionnaire was administered to parents and children. Uncorrected visual acuity (UCVA) was measured using an E Standard Logarithm Vision Acuity Chart (GB11533-2011) at baseline, 6-month and 1-year intervals. A random subsample (n = 391) participated in the clinic visits and underwent cycloplegia at the beginning and after 1 year.
  
  
  RESULTS
  The mean UCVA for the entire intervention group was significantly better than the entire control group after 1 year (P < 0.001). In the subgroup study, new onset of myopia and changes in refractive error towards myopia were direction during the study period was significantly lower in the intervention group than in the control group (3.70 % vs. 8.50 %, P = 0.048; -0.10 ± 0.65 D/year vs. -0.27 ± 0.52 D/year, P = 0.005). Changes in axial length and IOP were also significantly lower following the intervention group (0.16 ± 0.30 mm/year vs. 0.21 ± 0.21 mm/year, P = 0.034; -0.05 ± 2.78 mmHg/year vs. 0.67 ± 2.21 mmHg/year, P = 0.006).
  
  
  CONCLUSIONS
  Increasing outdoor activities prevented myopia onset and development, as well as axial growth and elevated IOP in children.
  
  
  BACKGROUND
  Current controlled trials NCT02271373.
authors.affiliation: Department of Maternal, Child and Adolescent Health, School of Public Health, Anhui Medical University, 81st Meishan Road, Hefei, 230032, Anhui Province, P.R China. jinjuxiangjjx@126.com.
authors.forename: Ju-Xiang
authors.initials: JX
authors.lastname: Jin
authors.affiliation: Department of Maternal, Child and Adolescent Health, School of Public Health, Anhui Medical University, 81st Meishan Road, Hefei, 230032, Anhui Province, P.R China. huawenjuan12010129@126.com.
authors.forename: Wen-Juan
authors.initials: WJ
authors.lastname: Hua
authors.affiliation: Health Center for Elementary and Middle School Students of Sujiatun District, Shenyang, Liaoning, China. jiangxuan196978@sina.com.
authors.forename: Xuan
authors.initials: X
authors.lastname: Jiang
authors.affiliation: Department of Maternal, Child and Adolescent Health, School of Public Health, Anhui Medical University, 81st Meishan Road, Hefei, 230032, Anhui Province, P.R China. xywu85@126.com.
authors.forename: Xiao-Yan
authors.initials: XY
authors.lastname: Wu
authors.affiliation: Shenyang Aier Eye Hospital, Shenyang, Liaoning, China. yangjiwen1975@vip.163.com.
authors.forename: Ji-Wen
authors.initials: JW
authors.lastname: Yang
authors.affiliation: Department of Maternal, Child and Adolescent Health, School of Public Health, Anhui Medical University, 81st Meishan Road, Hefei, 230032, Anhui Province, P.R China. ggpahmu@126.com.
authors.forename: Guo-Peng
authors.initials: GP
authors.lastname: Gao
authors.affiliation: Department of Maternal, Child and Adolescent Health, School of Public Health, Anhui Medical University, 81st Meishan Road, Hefei, 230032, Anhui Province, P.R China. fangyun1509@163.com.
authors.forename: Yun
authors.initials: Y
authors.lastname: Fang
authors.affiliation: Department of Ophthalmology, the Second Hospital of Anhui Medical University, Hefei, Anhui, China. tipcl10@yahoo.com.cn.
authors.forename: Chen-Lu
authors.initials: CL
authors.lastname: Pei
authors.affiliation: Department of Ophthalmology, the Second Hospital of Anhui Medical University, Hefei, Anhui, China. gnawgnos@163.com.
authors.forename: Song
authors.initials: S
authors.lastname: Wang
authors.affiliation: Education Bureau of Sujiatun District, Shenyang, Liaoning, China. Sjttwk@163.com.
authors.forename: Jie-Zheng
authors.initials: JZ
authors.lastname: Zhang
authors.affiliation: Department of Ophthalmology, the Second Hospital of Anhui Medical University, Hefei, Anhui, China. 13605517183@163.com.
authors.forename: Li-Ming
authors.initials: LM
authors.lastname: Tao
authors.affiliation: Department of Maternal, Child and Adolescent Health, School of Public Health, Anhui Medical University, 81st Meishan Road, Hefei, 230032, Anhui Province, P.R China. taofangbiao@126.com.|Anhui Provincial Key Laboratory of Population Health & Aristogenics, Hefei, Anhui, China. taofangbiao@126.com.
authors.forename: Fang-Biao
authors.initials: FB
authors.lastname: Tao
mesh_terms: D000293:Adolescent; D058452:Axial Length, Eye / Q000503:physiopathology; D002648:Child; D002681:China / Q000453:epidemiology; D018450:Disease Progression; D005260:Female; D006801:Humans; D007899:Leisure Activities; D008297:Male; D009216:Myopia / Q000175:diagnosis* / Q000453:epidemiology / Q000517:prevention & control*; D012424:Rural Population / Q000706:statistics & numerical data; D011795:Surveys and Questionnaires; D014505:Urban Population / Q000706:statistics & numerical data; D014792:Visual Acuity / Q000502:physiology