title: [Outdoor activity and myopia among 681 primary students in urban and rural regions of Beijing].
abstract: OBJECTIVE
  To explore the association between outdoor activity and myopia among 681 primary students from Beijing.
  
  
  METHODS
  School-based, cross-sectional investigation. Eye examination includes the visual acuity test, auto-refractor, slit lamp, ocular biometry and non-mydriatic fundus camera. Questionnaire includes regular items, near work, outdoor activity and social-economic status.
  
  
  RESULTS
  The mean time spent outdoors was 1.6 ± 0.8 hours daily. Time spent on outdoor sports and outdoor leisure were 0.7 ± 0.1 hours daily, 1.0 ± 0.8 hours daily, respectively. Mean time of outdoor activity in urban was 1.1 ± 0.4 hours daily, compared with 2.2 ± 0.8 hours daily in rural (P = 0.000). In grade-1, total time spent outdoors is significantly different between myopia and non-myopia (1.4 ± 0.6 vs 1.8 ± 0.8 hours daily, P = 0.000), similar to outdoor leisure (0.8 ± 0.6 vs 1.1 ± 0.9 hours daily, P = 0.000). The same trend was also found in grade-4.
  
  
  CONCLUSIONS
  The mean time spent outdoors was 1.6 ± 0.8 hours daily. Myopia spent a lower outdoor activity compared with non-myopia. More outdoor activity, e.g., in schools, may potentially be helpful to reduce the high prevalence of myopia in the young generation.
authors.affiliation: Tongren Eye Care Center, Beijing Tongren Hospital, Capital University of Medical Sciences, Beijing 100005, China.
authors.forename: Yin
authors.initials: Y
authors.lastname: Guo
authors.forename: Lijuan
authors.initials: L
authors.lastname: Liu
authors.affiliation: Beijing Tongren Ophthalmic Center, Beijing Institute of Ophthalmology, Capital University of Medical Sciences, Beijing 100005, China. Email: xlbio1@163.com.
authors.forename: Liang
authors.initials: L
authors.lastname: Xu
authors.forename: Yanyun
authors.initials: Y
authors.lastname: Lü
authors.forename: Ping
authors.initials: P
authors.lastname: Tang
authors.forename: Yi
authors.initials: Y
authors.lastname: Feng
mesh_terms: D002648:Child; D002681:China / Q000453:epidemiology; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007899:Leisure Activities; D008297:Male; D009043:Motor Activity; D009216:Myopia / Q000453:epidemiology*; D015995:Prevalence; D012424:Rural Population; D013177:Sports; D013334:Students; D011795:Surveys and Questionnaires; D014505:Urban Population