title: Danish Rural Eye Study: the association of preschool vision screening with the prevalence of amblyopia.
abstract: OBJECTIVE
  To determine the prevalence of amblyopia in Denmark before and after the initiation of the Danish national preschool vision screening programme.
  
  
  METHODS
  In a population-based cross-sectional study, 3826 participants of the Danish General Suburban Population Study (GESUS) aged 20 years and older from a Danish rural municipality received a complete general health examination and an ophthalmological interview and examination. This study included a comprehensive ophthalmologic interview, measurement of best corrected visual acuity (BCVA) in each eye, Hirschberg's test for strabismus and two 45-degree retinal fundus photographs of each eye. A complete ophthalmologic examination was performed when indicated.
  
  
  RESULTS
  The prevalence of monocular visual impairment (MVI) was 4.26% (95% CI, 3.66-4.95, n = 163). Amblyopia was the most common cause, accounting for 33%. The prevalence of amblyopia was 1.44% (95% CI, 1.01-1.81, n = 55), being higher among non-preschool vision screened persons compared to those who were offered (estimated 95% attendance) preschool vision screening (1.78%, n = 41, 95% CI 1.24-2.33 versus 0.44%, n = 2, 95% CI, 0.12-1.60, p = 0.024). The leading cause of amblyopia was anisometropia (45.5%, 25/55).
  
  
  CONCLUSIONS
  Amblyopia was the most common cause of MVI. Following the initiation of the Danish national preschool vision screening programme, which has an approximate attendance rate of 95%, the prevalence of amblyopia decreased by fourfold.
authors.affiliation: Department of Ophthalmology, Naestved Hospital, Naestved, Denmark.|The Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Tracy B
authors.initials: TB
authors.lastname: Høeg
authors.affiliation: Department of Ophthalmology, Naestved Hospital, Naestved, Denmark.
authors.forename: Birgitte
authors.initials: B
authors.lastname: Moldow
authors.affiliation: The Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.|Department of General Population Study, Nykøbing Falster Hospital, Nykøbing Falster, Denmark.
authors.forename: Christina
authors.initials: C
authors.lastname: Ellervik
authors.affiliation: Department of Ophthalmology, Capital Region Eye Clinic, Glostrup Hospital, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Kristian
authors.initials: K
authors.lastname: Klemp
authors.affiliation: Department of Ophthalmology, Naestved Hospital, Naestved, Denmark.
authors.forename: Ditte
authors.initials: D
authors.lastname: Erngaard
authors.affiliation: The Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.|Department of Ophthalmology, Capital Region Eye Clinic, Glostrup Hospital, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Morten
authors.initials: M
authors.lastname: la Cour
authors.affiliation: Department of Ophthalmology, Capital Region Eye Clinic, Glostrup Hospital, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Helena
authors.initials: H
authors.lastname: Buch
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D000550:Amblyopia / Q000453:epidemiology*; D003430:Cross-Sectional Studies; D003718:Denmark / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012424:Rural Population / Q000706:statistics & numerical data*; D015351:Vision Screening; D014792:Visual Acuity / Q000502:physiology; D019987:Persons with Visual Disabilities / Q000706:statistics & numerical data*; D055815:Young Adult
keywords: amblyopia; childhood vision screening; population-based; prevalence