title: Ethnic differences in refraction and ocular biometry in a population-based sample of 11-15-year-old Australian children.
abstract: OBJECTIVE
  To examine the prevalence of refractive error and distribution of ocular biometric parameters among major ethnic groups in a population-based sample of 11-15-year-old Australian children.
  
  
  METHODS
  The Sydney Myopia Study examined 2353 students (75.3% response) from a random cluster-sample of 21 secondary schools across Sydney. Examinations included cycloplegic autorefraction, and measures of corneal radius of curvature, anterior chamber depth, and axial length.
  
  
  RESULTS
  Participants mean age was 12.7 years (range 11.1-14.4); 49.4% were female. Overall, 60.0% of children had European Caucasian ethnicity, 15.0% East Asian, 7.1% Middle Eastern, and 5.5% South Asian. The most frequent refractive error was mild hyperopia (59.4%, 95% confidence interval (CI), 53.2-65.6), defined as spherical equivalent (SE) +0.50 to +1.99 D. Myopia (SE-0.50 D or less) was found in 11.9%, 95% (CI 6.6-17.2), and moderate hyperopia (SE> or =+2.00 D) in 3.5%, 95% (CI 2.8-4.1). Myopia prevalence was lower among European Caucasian children (4.6%, 95% CI 3.1-6.1) and Middle Eastern children (6.1%, 95% CI 1.3-11.0) than among East Asian (39.5%, 95%, CI 25.6-53.5) and South Asian (31.5%, 95%, CI 21.6-41.4) children. European Caucasian children had the most hyperopic mean SE (+0.82 D) and shortest mean axial length (23.23 mm). East Asian children had the most myopic mean SE (-0.69 D) and greatest mean axial length (23.86 mm).
  
  
  CONCLUSIONS
  The overall myopia prevalence in this sample was lower than in recent similar-aged European Caucasian population samples. East Asian children in our sample had both a higher prevalence of myopia and longer mean axial length.
authors.affiliation: Department of Ophthalmology and the Westmead Millennium Institute, Centre for Vision Research, University of Sydney, Sydney, Australia.
authors.forename: J M
authors.initials: JM
authors.lastname: Ip
authors.forename: S C
authors.initials: SC
authors.lastname: Huynh
authors.forename: D
authors.initials: D
authors.lastname: Robaei
authors.forename: A
authors.initials: A
authors.lastname: Kifley
authors.forename: K A
authors.initials: KA
authors.lastname: Rose
authors.forename: I G
authors.initials: IG
authors.lastname: Morgan
authors.forename: J J
authors.initials: JJ
authors.lastname: Wang
authors.forename: P
authors.initials: P
authors.lastname: Mitchell
mesh_terms: D000293:Adolescent; D001699:Biometry; D002648:Child; D003315:Cornea / Q000473:pathology; D003430:Cross-Sectional Studies; D005006:Ethnicity; D005260:Female; D006801:Humans; D008297:Male; D009517:New South Wales / Q000453:epidemiology; D015995:Prevalence; D012029:Refraction, Ocular / Q000502:physiology*; D012030:Refractive Errors / Q000453:epidemiology / Q000208:ethnology*