title: Measuring contrast sensitivity under different lighting conditions: comparison of three tests.
abstract: OBJECTIVE
  The purpose of this study was to evaluate three psychophysical tests for the measurement of contrast sensitivity (CS) and disability glare (DG) at different luminance levels.
  
  
  METHODS
  In 60 eyes of 60 individuals (group 1: 20 healthy eyes of young individuals; group 2: 20 healthy eyes of elderly subjects; group 3: 20 eyes with nuclear cataract), CS with best correction was measured twice with the Frankfurt-Freiburg Contrast and Acuity Test System (FF-CATS) and the Functional Acuity Contrast Test (FACT, 1.5 cycles per degree [cpd]) at 167 cd/m2 and 0.167 cd/m2, and with the Pelli-Robson Chart (PRC) at 100 cd/m2 with and without glare. Repeatability of test and retest, and discriminative ability between the different subgroups, were assessed for CS values.
  
  
  RESULTS
  Maximum CS values varied across tests. In all groups, highest CS values were obtained with the photopic FF-CATS. For FACT scores at 1.5 cpd, there was a ceiling effect for young subjects. CS scores obtained with the PRC were the lowest. The PRC had the best test-retest repeatability of all tests. Under mesopic conditions with glare, reliability was generally lower; the FF-CATS had the highest repeatability of the mesopic tests. The FF-CATS discriminated best between the different groups for all conditions.
  
  
  CONCLUSIONS
  There are large discrepancies in the test results between CS testing methods, especially under different lighting conditions. Results from different CS tests are not interchangeable.
authors.affiliation: Department of Ophthalmology, Johann Wolfgang Goethe-University, Frankfurt am Main, Germany.
authors.forename: Jens
authors.initials: J
authors.lastname: Bühren
authors.forename: Evdoxia
authors.initials: E
authors.lastname: Terzi
authors.forename: Michael
authors.initials: M
authors.lastname: Bach
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Wesemann
authors.forename: Thomas
authors.initials: T
authors.lastname: Kohnen
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology; D015350:Contrast Sensitivity / Q000502:physiology*; D004192:Discrimination, Psychological / Q000502:physiology*; D005260:Female; D019466:Glare; D006801:Humans; D008027:Light; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012016:Reference Values; D014787:Vision Tests / Q000379:methods*