title: Prevalence and 5- to 6-year incidence and progression of myopia and hyperopia in Australian schoolchildren.
abstract: OBJECTIVE
  To determine the prevalence, incidence, and change in refractive errors for Australian schoolchildren and examine the impact of ethnicity and sex.
  
  
  METHODS
  Population-based cohort study.
  
  
  METHODS
  The Sydney Adolescent Vascular and Eye Study, a 5- to 6-year follow-up of the Sydney Myopia Study, examined 2760 children in 2 age cohorts, 12 and 17 years. Longitudinal data were available for 870 and 1202 children in the younger and older cohorts, respectively.
  
  
  METHODS
  Children completed a comprehensive examination, including cycloplegic autorefraction (cyclopentolate 1%; Canon RK-F1). Myopia was defined as ≤-0.50 diopters (D) and hyperopia as ≥+2.00 D right eye spherical equivalent refraction.
  
  
  METHODS
  Baseline and follow-up refraction.
  
  
  RESULTS
  Prevalence of myopia increased between baseline and follow-up for both the younger (1.4%-14.4%; P<0.0001) and older cohorts (13.0%-29.6%; P<0.0001). The annual incidence of myopia was 2.2% in the younger cohort and 4.1% in the older. Children of East Asian ethnicity had a higher annual incidence of myopia (younger 6.9%, older 7.3%) than European Caucasian children (younger 1.3%, older 2.9%; all P<0.0001). The prevalence of myopia in European Caucasian children almost doubled between the older (4.4%; 95% confidence interval [CI], 3.0-5.8) and younger samples (8.6%; 95% CI, 6.7-10.6) when both were aged 12 years. Children with ametropia at baseline were more likely to have a significant shift in refraction (hyperopia: odds ratio [OR], 3.4 [95% CI, 1.2-9.8]; myopia: OR, 6.3 [95% CI, 3.7-10.8]) compared with children with no refractive error. There was no significant difference in myopia progression between children of European Caucasian and East Asian ethnicity (P = 0.7).
  
  
  CONCLUSIONS
  In Sydney, myopia prevalence (14.4%, 29.6%) and incidence (2.2%, 4.1%) was low for both age cohorts, compared with other locations. However, in European Caucasian children at age 12, the significantly higher prevalence of myopia in the younger sample suggests a rise in prevalence, consistent with international trends. Progression of myopia was similar for children of East Asian and European Caucasian ethnicity, but lower than reported in children of East Asian ethnicity in East Asia, suggesting that environmental differences may have some impact on progression.
authors.affiliation: Discipline of Orthoptics, Faculty of Health Sciences, University of Sydney, Sydney, New South Wales, Australia.
authors.forename: Amanda N
authors.initials: AN
authors.lastname: French
authors.forename: Ian G
authors.initials: IG
authors.lastname: Morgan
authors.forename: George
authors.initials: G
authors.lastname: Burlutsky
authors.forename: Paul
authors.initials: P
authors.lastname: Mitchell
authors.forename: Kathryn A
authors.initials: KA
authors.lastname: Rose
mesh_terms: D000293:Adolescent; D002648:Child; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D018450:Disease Progression; D005006:Ethnicity; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006956:Hyperopia / Q000175:diagnosis / Q000453:epidemiology*; D015994:Incidence; D008297:Male; D009216:Myopia / Q000175:diagnosis / Q000453:epidemiology*; D009517:New South Wales / Q000453:epidemiology; D015995:Prevalence; D012029:Refraction, Ocular / Q000502:physiology