title: Age differences in spatial contrast sensitivity are not the result of changes in subjects' criteria or psychophysical performance.
abstract: OBJECTIVE
  To analyze separately the sensory and nonsensory aspects of reductions in contrast sensitivity with age.
  
  
  METHODS
  Two-alternative forced choice psychometric functions were fitted with a three-parameter Weibull function, which independently estimated threshold, slope, and upper asymptote of the functions.
  
  
  RESULTS
  There were no changes in slope or upper asymptote with age, but contrast sensitivity decreased with age.
  
  
  CONCLUSIONS
  Most studies of decreased visual function in the elderly are difficult to interpret because possible nonsensory effects are ignored. This paper illustrates a method that can be used to demonstrate a true sensory decline with age.
authors.affiliation: State College of Optometry, State University of New York, New York.
authors.forename: D
authors.initials: D
authors.lastname: Yager
authors.forename: B L
authors.initials: BL
authors.lastname: Beard
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology*; D015350:Contrast Sensitivity / Q000502:physiology*; D006801:Humans; D008875:Middle Aged; D011597:Psychomotor Performance / Q000502:physiology*; D011601:Psychophysics / Q000379:methods; D013028:Space Perception / Q000502:physiology*