title: Refractive error and visual impairment in school children in Northern Ireland.
abstract: OBJECTIVE
  To describe the prevalence of refractive error (myopia and hyperopia) and visual impairment in a representative sample of white school children.
  
  
  METHODS
  The Northern Ireland Childhood Errors of Refraction study, a population-based cross-sectional study, examined 661 white 12-13-year-old and 392 white 6-7-year-old children between 2006 and 2008. Procedures included assessment of monocular logarithm of the minimum angle of resolution (logMAR), visual acuity (unaided and presenting) and binocular open-field cycloplegic (1% cyclopentolate) autorefraction. Myopia was defined as -0.50DS or more myopic spherical equivalent refraction (SER) in either eye, hyperopia as > or =+2.00DS SER in either eye if not previously classified as myopic. Visual impairment was defined as >0.30 logMAR units (equivalent to 6/12).
  
  
  RESULTS
  Levels of myopia were 2.8% (95% CI 1.3% to 4.3%) in younger and 17.7% (95% CI 13.2% to 22.2%) in older children: corresponding levels of hyperopia were 26% (95% CI 20% to 33%) and 14.7% (95% CI 9.9% to 19.4%). The prevalence of presenting visual impairment in the better eye was 3.6% in 12-13-year-old children compared with 1.5% in 6-7-year-old children. Almost one in four children fails to bring their spectacles to school.
  
  
  CONCLUSIONS
  This study is the first to provide robust population-based data on the prevalence of refractive error and visual impairment in Northern Irish school children. Strategies to improve compliance with spectacle wear are required.
authors.affiliation: School of Biomedical Sciences, University of Ulster, Cromore Road, Coleraine, BT52 1SA, UK. l.odonoghue@ulster.ac.uk
authors.forename: L
authors.initials: L
authors.lastname: O'Donoghue
authors.forename: J F
authors.initials: JF
authors.lastname: McClelland
authors.forename: N S
authors.initials: NS
authors.lastname: Logan
authors.forename: A R
authors.initials: AR
authors.lastname: Rudnicka
authors.forename: C G
authors.initials: CG
authors.lastname: Owen
authors.forename: K J
authors.initials: KJ
authors.lastname: Saunders
mesh_terms: D002648:Child; D005139:Eyeglasses / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D006956:Hyperopia / Q000453:epidemiology* / Q000503:physiopathology; D008297:Male; D009216:Myopia / Q000453:epidemiology* / Q000503:physiopathology; D009660:Northern Ireland / Q000453:epidemiology; D010349:Patient Compliance / Q000706:statistics & numerical data; D015995:Prevalence; D012959:Socioeconomic Factors; D014786:Vision Disorders / Q000453:epidemiology* / Q000503:physiopathology; D014792:Visual Acuity; D044465:White People