title: Comparison of refraction and ocular biometry in European Caucasian children living in Northern Ireland and Sydney, Australia.
abstract: OBJECTIVE
  To compare refraction and ocular biometry in European Caucasian children aged 6 to 7 years and 12 to 13 years, living in Sydney, Australia, and Northern Ireland.
  
  
  METHODS
  All children had a comprehensive eye examination, including cycloplegic (cyclopentolate 1%) autorefraction and ocular biometry. Hyperopia was defined as a right spherical equivalent refraction (SER) of ≥+2.00 diopters (D), myopia as ≤-0.50 D, and astigmatism as a cylindrical error of ≥1.00 D.
  
  
  RESULTS
  The mean SER was similar at age 6 to 7 years (P = 0.9); however, at 12 to 13 years, children in Northern Ireland had a significantly less hyperopic mean SER (+0.66 D) than children in Sydney (+0.83 D, P = 0.008). The prevalence of myopia, hyperopia, and astigmatism was significantly greater in Northern Ireland than Sydney at both ages (all P < 0.03). The distribution of refraction was highly leptokurtic in both samples, but less so in Northern Ireland (kurtosis: 6-7 years of age, 7.2; 12-13 years of age, 5.9) than Sydney (kurtosis: 6-7 years of age, 15.0; 12-13 years of age, 19.5).
  
  
  CONCLUSIONS
  European Caucasian children in Northern Ireland have a greater prevalence of myopia, hyperopia, and astigmatism when compared to children living in Sydney. Risk factors for myopia such as parental myopia, parental education, and educational standards do not appear to explain the differences. Further work on levels of near work and time spent outdoors is required.
authors.affiliation: Discipline of Orthoptics, Faculty of Health Sciences, University of Sydney, Sydney, NSW, Australia.
authors.forename: Amanda N
authors.initials: AN
authors.lastname: French
authors.forename: Lisa
authors.initials: L
authors.lastname: O'Donoghue
authors.forename: Ian G
authors.initials: IG
authors.lastname: Morgan
authors.forename: Kathryn J
authors.initials: KJ
authors.lastname: Saunders
authors.forename: Paul
authors.initials: P
authors.lastname: Mitchell
authors.forename: Kathryn A
authors.initials: KA
authors.lastname: Rose
mesh_terms: D000065:Accommodation, Ocular / Q000502:physiology; D000293:Adolescent; D001699:Biometry / Q000379:methods*; D002648:Child; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D009517:New South Wales / Q000453:epidemiology; D009660:Northern Ireland / Q000453:epidemiology; D012029:Refraction, Ocular / Q000502:physiology*; D012030:Refractive Errors / Q000208:ethnology / Q000503:physiopathology*; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires; D058609:Visual Field Tests / Q000379:methods*; D044465:White People