title: Prevalence of refractive errors in young and middle-aged adults in Norway.
abstract: OBJECTIVE
  To determine the prevalence of refractive errors in the young and middle-aged adult population in Norway.
  
  
  METHODS
  Refractive errors were measured in a population-based sample of young (20-25 years) and middle-aged (40-45 years) adults participating in the Helseundersøkelse i Nord Trøndelag (HUNT) Health Study, conducted in the County of Nord-Trøndelag in Norway.
  
  
  RESULTS
  A total of 3137 persons (1248 young and 1889 middle-aged adults) with corrected visual acuity > or = 0.5 (in either eye) were included in the study. The prevalence of myopia was 35.0% in the young adult group and 30.3% in the middle-aged group. Myopia was significantly higher in women aged 20-25 years (36.4%) than in men aged 40-45 years (28.1%). Prevalence of hyperopia increased with age from 13.2% (20-25 years) to 17.4% (40-45 years). The highest rate of hyperopia (20.1%) was encountered in middle-aged women.
  
  
  CONCLUSIONS
  The results show a slightly higher prevalence of myopia in the general population of Norway than previously estimated.
authors.affiliation: Department of Ophthalmology, Institute of Clinical Neurosciences, Norwegian University of Science and Technology, Trondheim, Norway. anna.midelfart@medisin.ntnu.no
authors.forename: Anna
authors.initials: A
authors.lastname: Midelfart
authors.forename: Bettina
authors.initials: B
authors.lastname: Kinge
authors.forename: Sven
authors.initials: S
authors.lastname: Midelfart
authors.forename: Stian
authors.initials: S
authors.lastname: Lydersen
mesh_terms: D000328:Adult; D017677:Age Distribution; D005260:Female; D006306:Health Surveys; D006801:Humans; D006956:Hyperopia / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000453:epidemiology*; D009664:Norway / Q000453:epidemiology; D015995:Prevalence; D017678:Sex Distribution