title: Repeatability and intercorrelations of standard vision tests as a function of age.
abstract: OBJECTIVE
  We assessed repeatability and intercorrelations of five standard vision tests in subjects with normal vision.
  
  
  METHODS
  Seventy-eight subjects (aged 21 to 68 years) completed five measurements each of high- and low-contrast visual acuity, near visual acuity and contrast sensitivity (Pelli-Robson chart).
  
  
  RESULTS
  Except for correlations between high- and low-contrast visual acuity (r = 0.78), intercorrelations between tests were low to moderate (r < 0.5). For each measure, variability for the group was about one line on the chart (one triplet for the Pelli-Robson chart) and the minimum variability for an individual subject was about one third of this. On average, 1 to 2 lines can be expected to be lost over the normal lifespan on each test. Variability in responses did not increase significantly with age for any test.
  
  
  CONCLUSIONS
  The criterion for judging change on commonly used clinical vision tests is about one line for subjects over a wide age range.
authors.affiliation: Centre for Eye Research, School of Optometry, Queensland University of Technology, Brisbane, Australia. j.lovie-kitchin@qut.edu.au
authors.forename: J E
authors.initials: JE
authors.lastname: Lovie-Kitchin
authors.forename: B
authors.initials: B
authors.lastname: Brown
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D009819:Office Visits / Q000706:statistics & numerical data*; D012016:Reference Values; D014787:Vision Tests / Q000592:standards* / Q000706:statistics & numerical data*; D014792:Visual Acuity / Q000502:physiology*