title: Changes in visual acuity in a population over a 15-year period: the Beaver Dam Eye Study.
abstract: OBJECTIVE
  To describe the change in visual acuity in a 15-year period.
  
  
  METHODS
  Population-based study.
  
  
  METHODS
  setting: Beaver Dam, Wisconsin. participants: 4068 persons 43 to 86 years of age at the time of a baseline examination in 1988 to 1990, and with follow-up examinations every five years thereafter. observation procedures: Best-corrected visual acuity after refraction, assessed by a modification of the ETDRS protocol. main outcome measure: Doubling of the visual angle; incidence of visual impairment.
  
  
  RESULTS
  Eight percent of the population developed impaired vision (20/40 or worse), 0.8% developed severe visual impairment (20/200 or worse), 7% had doubling of the visual angle, and 2% had improved vision. People 75 years of age or older at baseline were more likely to develop impaired vision (odds ratio [OR] 12.8, 95% confidence interval [CI] 9.6 to 17.1, P < .001), doubling of the visual angle (OR 7.8, 95% CI 5.6 to 10.7, P < .001), and severe visual impairment (OR 20.6, 95% CI 9.5 to 44.8, P<0.001) compared with people younger than 75 years of age.
  
  
  CONCLUSIONS
  These data provide population-based estimates of the cumulative 15-year incidence of loss of vision over a wide spectrum of ages. In people 75 years of age or older the cumulative incidence of visual impairment accounting for the competing risk of death is 25%, of which 4% is severe, indicating a public health problem of considerable proportions as the US population in this age is expected to increase by 55% from 18 million in the year 2005 to 28 million by the year 2025.
authors.affiliation: Department of Ophthalmology and Visual Sciences, University of Wisconsin School of Medicine and Public Health, Madison, WI 53726-2336, USA. kleinr@epi.ophth.wisc.edu
authors.forename: Ronald
authors.initials: R
authors.lastname: Klein
authors.forename: Barbara E K
authors.initials: BE
authors.lastname: Klein
authors.forename: Kristine E
authors.initials: KE
authors.lastname: Lee
authors.forename: Karen J
authors.initials: KJ
authors.lastname: Cruickshanks
authors.forename: Ronald E
authors.initials: RE
authors.lastname: Gangnon
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D044382:Population Groups; D014786:Vision Disorders / Q000453:epidemiology* / Q000503:physiopathology; D014792:Visual Acuity / Q000502:physiology*; D019987:Persons with Visual Disabilities / Q000706:statistics & numerical data*; D014922:Wisconsin / Q000453:epidemiology