title: Age-Specific Prevalence of Visual Impairment and Refractive Error in Children Aged 3-10 Years in Shanghai, China.
abstract: OBJECTIVE
  We assessed changes in age-specific prevalence of refractive error at the time of starting school, by comparing preschool and school age cohorts in Shanghai, China.
  
  
  METHODS
  A cross-sectional study was done in Jiading District, Shanghai during November and December 2013. We randomly selected 7 kindergartens and 7 primary schools, with probability proportionate to size. Chinese children (n = 8398) aged 3 to 10 years were enumerated, and 8267 (98.4%) were included. Children underwent distance visual acuity assessment and refraction measurement by cycloplegic autorefraction and subjective refraction.
  
  
  RESULTS
  The prevalence of uncorrected visual acuity (UCVA), presenting visual acuity, and best-corrected visual acuity in the better eye of ≤20/40 was 19.8%, 15.5%, and 1.7%, respectively. Among those with UCVA ≤ 20/40, 93.2% could achieve visual acuity of ≥20/32 with refraction. Only 28.7% (n = 465) of children with UCVA in the better eye of ≤20/40 wore glasses. Prevalence of myopia (spherical equivalent ≤-0.5 diopters [D] in at least one eye) increased from 1.78% in 3-year-olds to 52.2% in 10-year-olds, while prevalence of hyperopia (spherical equivalent ≥+2.0 D) decreased from 17.8% among 3-year-olds to 2.6% by 10 years of age. After adjusting for age, attending elite "high-level" school was statistically associated with greater myopia prevalence.
  
  
  CONCLUSIONS
  The prevalence of myopia was lower or comparable to that reported in other populations from age 3 to 5 years, but increased dramatically after 6 years, consistent with a strong environmental role of schooling on myopia development.
authors.affiliation: Department of Preventative Ophthalmology, Shanghai Eye Disease Prevention and Treatment Center, Shanghai Eye Hospital, Shanghai, China 2Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University, Shanghai, China.
authors.forename: Yingyan
authors.initials: Y
authors.lastname: Ma
authors.affiliation: Eye & ENT Hospital, Fudan University, Shanghai, China.
authors.forename: Xiaomei
authors.initials: X
authors.lastname: Qu
authors.affiliation: Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University, Shanghai, China.
authors.forename: Xiaofeng
authors.initials: X
authors.lastname: Zhu
authors.affiliation: Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University, Shanghai, China.
authors.forename: Xun
authors.initials: X
authors.lastname: Xu
authors.affiliation: Department of Preventative Ophthalmology, Shanghai Eye Disease Prevention and Treatment Center, Shanghai Eye Hospital, Shanghai, China.
authors.forename: Jianfeng
authors.initials: J
authors.lastname: Zhu
authors.affiliation: Brien Holden Vision Institute, Rupert Myers Building, Kensington, New South Wales, Sydney, Australia.
authors.forename: Padmaja
authors.initials: P
authors.lastname: Sankaridurg
authors.affiliation: Department of Preventative Ophthalmology, Shanghai Eye Disease Prevention and Treatment Center, Shanghai Eye Hospital, Shanghai, China 5School of Public Health, Fudan University, Shanghai, China.
authors.forename: Senlin
authors.initials: S
authors.lastname: Lin
authors.affiliation: Department of Preventative Ophthalmology, Shanghai Eye Disease Prevention and Treatment Center, Shanghai Eye Hospital, Shanghai, China.
authors.forename: Lina
authors.initials: L
authors.lastname: Lu
authors.affiliation: Shanghai Shen Kang Hospital Development Center, Shanghai, China.
authors.forename: Rong
authors.initials: R
authors.lastname: Zhao
authors.affiliation: Department of Maternal and Child Health, School of Public Health, Key Laboratory of Public Health Safety, Ministry of Education, Fudan University, Shanghai, China.
authors.forename: Ling
authors.initials: L
authors.lastname: Wang
authors.affiliation: Department of Maternal and Child Health, School of Public Health, Key Laboratory of Public Health Safety, Ministry of Education, Fudan University, Shanghai, China.
authors.forename: Huijing
authors.initials: H
authors.lastname: Shi
authors.affiliation: Department of Maternal and Child Health, School of Public Health, Key Laboratory of Public Health Safety, Ministry of Education, Fudan University, Shanghai, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Tan
authors.affiliation: Department of Maternal and Child Health, School of Public Health, Key Laboratory of Public Health Safety, Ministry of Education, Fudan University, Shanghai, China.
authors.forename: Xiaofang
authors.initials: X
authors.lastname: You
authors.affiliation: Jiading Center for Disease Prevention and Control, Shanghai, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Yuan
authors.affiliation: Jiading Center for Disease Prevention and Control, Shanghai, China.
authors.forename: Sifei
authors.initials: S
authors.lastname: Sun
authors.affiliation: Department of Preventative Ophthalmology, Shanghai Eye Disease Prevention and Treatment Center, Shanghai Eye Hospital, Shanghai, China.
authors.forename: Mingjin
authors.initials: M
authors.lastname: Wang
authors.affiliation: Department of Preventative Ophthalmology, Shanghai Eye Disease Prevention and Treatment Center, Shanghai Eye Hospital, Shanghai, China 7Department of Maternal and Child Health, School of Public Health, Key Laboratory of Public Health Safety, Ministry of Education, Fudan University, Shanghai, China.
authors.forename: Xiangui
authors.initials: X
authors.lastname: He
authors.affiliation: Department of Preventative Ophthalmology, Shanghai Eye Disease Prevention and Treatment Center, Shanghai Eye Hospital, Shanghai, China 2Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University, Shanghai, China.
authors.forename: Haidong
authors.initials: H
authors.lastname: Zou
authors.affiliation: TREE Centre, Centre for Public Health, Queen's University Belfast, Northern Ireland, United Kingdom 10Zhongshan Ophthalmic Centre, Sun Yat-sen University, Guangzhou, China 11Orbis International, New York, New York, United States.
authors.forename: Nathan
authors.initials: N
authors.lastname: Congdon
mesh_terms: D017677:Age Distribution; D000367:Age Factors; D002648:Child; D002675:Child, Preschool; D002681:China / Q000453:epidemiology; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D015995:Prevalence; D011379:Prognosis; D012029:Refraction, Ocular / Q000502:physiology*; D012030:Refractive Errors / Q000453:epidemiology* / Q000503:physiopathology / Q000534:rehabilitation; D012307:Risk Factors; D014787:Vision Tests; D014792:Visual Acuity; D019987:Persons with Visual Disabilities