title: Prevalence and causes of visual impairment and blindness among 9980 Scandinavian adults: the Copenhagen City Eye Study.
abstract: OBJECTIVE
  To investigate the age-specific prevalence and causes of visual impairment and blindness in an epidemiologic study of an adult Scandinavian population.
  
  
  METHODS
  Population-based, cross-sectional study.
  
  
  METHODS
  The study population was composed of 9980 persons, ages 20 to 84, from the general population of Copenhagen, Denmark.
  
  
  METHODS
  This study is based on the third Copenhagen City Heart Study (CCHS III). Participants who reported visual impairment or blindness or had difficulty reading newspaper type and used prescribed eye medications were contacted from 1999 through 2000 and asked to complete a standardized interview concerning their ophthalmologic history. Verification of objective ophthalmologic data was done with a validated questionnaire response method.
  
  
  METHODS
  Best-corrected visual acuity in the better eye and primary causes of visual impairment and blindness. Visual impairment was defined as visual acuity worse than 20/40 but better than 20/200, and blindness was defined as visual acuity of 20/200 or worse.
  
  
  RESULTS
  The age-standardized prevalence rates of visual impairment and blindness were 0.66% and 0.20%, respectively, and rose significantly with age (P<0.001). For persons 20 to 64 years, myopia-related retinal disorders, diabetic retinopathy, optic neuropathy, and retinitis pigmentosa were the most common causes of impaired vision. For persons 65 to 84 years, cataract was the most common cause of visual impairment, whereas age-related macular degeneration was the major cause of blindness.
  
  
  CONCLUSIONS
  Visual impairment and blindness are strongly associated with increasing age, and the causes are determined by age. Among persons aged 20 to 64 years, an intervention for the predominating eye diseases might have some effect. Among those aged 65 to 84 years, cataract surgery could reduce visual impairment by one third.
authors.affiliation: Department of Ophthalmology, National University Hospital (Rigshospitalet), Copenhagen, Denmark. hbh@dadlnet.dk
authors.forename: Helena
authors.initials: H
authors.lastname: Buch
authors.forename: Troels
authors.initials: T
authors.lastname: Vinding
authors.forename: Morten
authors.initials: M
authors.lastname: La Cour
authors.forename: Merete
authors.initials: M
authors.lastname: Appleyard
authors.forename: Gorm B
authors.initials: GB
authors.lastname: Jensen
authors.forename: Niels Vesti
authors.initials: NV
authors.lastname: Nielsen
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D001766:Blindness / Q000453:epidemiology* / Q000209:etiology*; D015984:Causality; D003430:Cross-Sectional Studies; D003718:Denmark / Q000453:epidemiology; D005128:Eye Diseases / Q000150:complications; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012307:Risk Factors; D011795:Surveys and Questionnaires; D015354:Vision, Low / Q000453:epidemiology* / Q000209:etiology*; D014792:Visual Acuity; D019987:Persons with Visual Disabilities / Q000706:statistics & numerical data*