title: Ethnic differences in the impact of parental myopia: findings from a population-based study of 12-year-old Australian children.
abstract: OBJECTIVE
  To examine the influences of ethnicity, parental myopia, and near work on spherical equivalent refraction (SER) and axial length (AL) in a population-based sample of 12-year-old Australian children.
  
  
  METHODS
  Year-7 children in the Sydney Myopia Study (n = 2353, 75.3% response) underwent an ophthalmic examination including cycloplegic autorefraction (1% cyclopentolate) and ocular biometry (IOLMaster; Carl Zeiss Meditec GmbH, Jena, Germany). Data for parental myopia, ethnicity, near work, and outdoor activities were derived from questionnaires and were available for 1781 children. Optical prescriptions of parents were sought if the spectacles were used.
  
  
  RESULTS
  The prevalence of myopia in the children increased with the number of myopic parents (7.6%, 14.9%, and 43.6% for no, one, or two myopic parents). In parallel, the mean SER (+/-SE of the mean) was more negative (0.70 +/- 0.08, 0.34 +/- 0.09, and -0.55 +/- 0.34 D), and the mean AL was longer (23.32 +/- 0.05, 23.44 +/- 0.06, and 23.62 +/- 0.16 mm) after adjustment for demographic and environmental factors. In multivariate analyses, odds of childhood myopia did not change with higher levels of near work (odds ratio [OR] = 1.01; 95% confidence interval [CI] = 0.99-1.03). Interactions between parental myopia and ethnicity were significant for SER and AL (both P < 0.0001), reflecting greater decreases in SER and greater increases in AL with the number of myopic parents in the children of East Asian ethnicity than in the children of European Caucasian ethnicity. In the nonmyopic children, there was no association between parental myopia and AL.
  
  
  CONCLUSIONS
  In this sample, parental myopia was associated with more myopic SER and longer AL, with significant ethnic interactions.
authors.affiliation: Centre for Vision Research (Department of Ophthalmology and Westmead Millennium Institute), University of Sydney, and the Vision Co-operative Research Centre, University of New South Wales, Sydney Australia.
authors.forename: Jenny M
authors.initials: JM
authors.lastname: Ip
authors.forename: Son C
authors.initials: SC
authors.lastname: Huynh
authors.forename: Dana
authors.initials: D
authors.lastname: Robaei
authors.forename: Kathryn A
authors.initials: KA
authors.lastname: Rose
authors.forename: Ian G
authors.initials: IG
authors.lastname: Morgan
authors.forename: Wayne
authors.initials: W
authors.lastname: Smith
authors.forename: Annette
authors.initials: A
authors.lastname: Kifley
authors.forename: Paul
authors.initials: P
authors.lastname: Mitchell
mesh_terms: D000293:Adolescent; D044466:Asian People / Q000208:ethnology*; D002648:Child; D016241:Child of Impaired Parents; D005139:Eyeglasses; D005260:Female; D006801:Humans; D008297:Male; D009216:Myopia / Q000208:ethnology* / Q000628:therapy; D009517:New South Wales / Q000453:epidemiology; D010290:Parents; D015995:Prevalence; D012029:Refraction, Ocular / Q000502:physiology; D011795:Surveys and Questionnaires; D044465:White People / Q000208:ethnology*