title: Changes in visual acuity in a population over a 10-year period : The Beaver Dam Eye Study.
abstract: OBJECTIVE
  To describe the change in visual acuity in a 10-year period.
  
  
  METHODS
  Population-based cohort study.
  
  
  METHODS
  Included 3684 persons 43 to 86 years of age at the time of a baseline examination in 1988 to 1990, living in Beaver Dam, Wisconsin, at a follow-up examination in 1993 to 1995 and/or 1998 to 2000.
  
  
  METHODS
  Best-corrected visual acuity was measured, after refraction, with logarithm of the minimum angle of resolution charts using a modification of the Early Treatment Diabetic Retinopathy Study protocol.
  
  
  METHODS
  Doubling of the visual angle and incidence of visual impairment.
  
  
  RESULTS
  The change in the mean number of letters read correctly over the 10-year period varied in the right eye from -0.9 (standard deviation [SD] = 5.5) and in the left eye from -1.2 (SD = 6.6) in people between 43 and 54 years of age to -11.0 (SD = 20.0) in the right eye and -12.6 (SD = 20.4) in the left eye in people 75 years of age or older (n = 184) at baseline. Over the 10-year period, 5.9% of the population had impaired vision (20/40 or worse in the better eye) develop, 0.8% had severe visual impairment (20/200 or worse in the better eye) develop, 4.8% had doubling of the visual angle, and 3.9% had improved vision. People who were 75 years of age or older at baseline were 15.0 times (95% confidence interval [CI], 10.9-20.6; P < 0.001) as likely to have impaired vision develop, 9.3 times (95% CI, 6.5-13.3; P < 0.001) as likely to have doubling of the visual angle, and 19.8 times as likely (95% CI, 8.4-46.4; P < or = 0.001) to have severe visual impairment develop than people younger than 75 years of age at baseline. For the 82 persons 75 years of age or older, currently residing in a nursing or group home at follow-up, they were 2.6 times (95% CI, 1.45-4.52) as likely to have impaired vision develop, 1.6 times (95% CI, 0.47-5.62) as likely to have severely impaired vision develop, and 3.6 times (95% CI, 1.96-6.78) as likely to have had a doubling of the visual angle than those not residing in a nursing or group home at follow-up.
  
  
  CONCLUSIONS
  These data provide precise population-based estimates of the 10-year incidence of loss of vision over a wide spectrum of ages and show that decreased visual acuity in people 75 years of age after 10 years is a common finding, especially in those who are admitted to nursing or group homes.
authors.affiliation: Department of Ophthalmology and Visual Sciences, University of Wisconsin Medical School, Madison, Wisconsin 53705-2397, USA.
authors.forename: R
authors.initials: R
authors.lastname: Klein
authors.forename: B E
authors.initials: BE
authors.lastname: Klein
authors.forename: K E
authors.initials: KE
authors.lastname: Lee
authors.forename: K J
authors.initials: KJ
authors.lastname: Cruickshanks
authors.forename: R J
authors.initials: RJ
authors.lastname: Chappell
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D003710:Demography; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D017678:Sex Distribution; D014786:Vision Disorders / Q000453:epidemiology*; D014787:Vision Tests; D014792:Visual Acuity; D014922:Wisconsin / Q000453:epidemiology