title: Reliability and consistency of dark-adapted psychophysical measures in advanced eye disease.
abstract: OBJECTIVE
  To establish reliable vision measures allowing functional monitoring in patients with severe vision loss.
  
  
  METHODS
  Legally blind and normally sighted subjects were enrolled in a repeated-measures study to determine the reproducibility of psychophysical vision measures under scotopic conditions. The tests included dark adaptometry, dark-adapted, full-field flash testing, and dark-adapted macular thresholds, obtained by using a perimeter with 500- and 650-nm targets. Two to five test repetitions were performed on the better eye of each subject at monthly intervals. Subject groups included retinitis pigmentosa (RP; n = 33), macular disease (MD; n = 14), optic nerve disease (ON; n = 4), diabetic retinopathy (DR; n = 5), and other retinal diseases (OR; n = 9), and normally sighted control (CTL; n = 12).
  
  
  RESULTS
  Dark adaptometry timing yielded mean coefficients of variation for subjects across all groups that averaged approximately 20% throughout the test. For dark-adapted perimetry, the coefficients of repeatability (CR(.95)) were <7 dB (CTL), <8 dB (OR), <6 dB (ON and RP), and <15 dB (MD). Full-field flash test CR(.95) by group varied from 5 to 15 dB, and most low-vision groups performed more reliably than CTL subjects.
  
  
  CONCLUSIONS
  Dark-adapted psychophysical tests can provide reproducible vision measures in subjects with severe visual impairments, and these tests would be useful in monitoring outcomes in future clinical trials to reverse, halt, or slow vision loss. The most valuable measure of remaining vision was the dark-adapted, full-field flash test, as it produced repeatable results at all levels of vision loss and for all disease states included in this study.
authors.affiliation: Lions Vision Center, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland 21205-2020, USA. abittne1@jhmi.edu
authors.forename: Ava K
authors.initials: AK
authors.lastname: Kiser
authors.forename: Derek
authors.initials: D
authors.lastname: Mladenovich
authors.forename: Fariba
authors.initials: F
authors.lastname: Eshraghi
authors.forename: Debra
authors.initials: D
authors.lastname: Bourdeau
authors.forename: Gislin
authors.initials: G
authors.lastname: Dagnelie
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001766:Blindness / Q000503:physiopathology*; D003623:Dark Adaptation / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010775:Photic Stimulation; D011601:Psychophysics; D015203:Reproducibility of Results; D012160:Retina / Q000503:physiopathology*; D012684:Sensory Thresholds; D014787:Vision Tests / Q000379:methods; D015354:Vision, Low / Q000503:physiopathology*; D014792:Visual Acuity / Q000502:physiology*; D058609:Visual Field Tests; D014794:Visual Fields / Q000502:physiology