title: Refractive errors in Singapore and Xiamen, China--a comparative study in school children aged 6 to 7 years.
abstract: OBJECTIVE
  To compare and contrast the prevalence of myopia and other refractive errors in Xiamen city, Xiamen countryside (Southern China), and Singapore.
  
  
  METHODS
  One hundred thirty-two schoolchildren aged 6 to 7 years from Xiamen city, 104 from Xiamen countryside, and 146 from Singapore city were recruited to join the study. Cycloplegic autorefraction, keratometry, and biometry measurements were performed on all children.
  
  
  RESULTS
  The prevalence of myopia was 12.3% in Singapore city, 9.1% in Xiamen city, and 3.9% in Xiamen countryside. The prevalence of astigmatism was higher in Singapore compared with Xiamen. The rates of hyperopia and anisometropia were similar in all three locations.
  
  
  CONCLUSIONS
  The myopia rate in Singapore city was higher than in Xiamen city; the lowest rates were found in Xiamen countryside. As the Chinese population from all three sites is of similar genetic stock (predominantly from Southern China), it is postulated that the differences in myopia rates in these three localities may be related to environmental factors.
authors.affiliation: Xiamen Eye Center, Xiamen Eye Institute, China. ykzxywk@public.xm.fj.cn
authors.forename: M Z
authors.initials: MZ
authors.lastname: Zhan
authors.forename: S M
authors.initials: SM
authors.lastname: Saw
authors.forename: R Z
authors.initials: RZ
authors.lastname: Hong
authors.forename: Z F
authors.initials: ZF
authors.lastname: Fu
authors.forename: H
authors.initials: H
authors.lastname: Yang
authors.forename: Y B
authors.initials: YB
authors.lastname: Shui
authors.forename: M K
authors.initials: MK
authors.lastname: Yap
authors.forename: S J
authors.initials: SJ
authors.lastname: Chew
mesh_terms: D015858:Anisometropia / Q000453:epidemiology; D001251:Astigmatism / Q000453:epidemiology; D002648:Child; D002681:China / Q000453:epidemiology; D005260:Female; D006801:Humans; D006956:Hyperopia / Q000453:epidemiology; D008297:Male; D009216:Myopia / Q000453:epidemiology; D015995:Prevalence; D012030:Refractive Errors / Q000453:epidemiology*; D015203:Reproducibility of Results; D012846:Singapore / Q000453:epidemiology; D014787:Vision Tests