title: Adaptation mechanisms, eccentricity profiles, and clinical implementation of red-on-white perimetry.
abstract: OBJECTIVE
  To determine the visual adaptation and retinal eccentricity profiles for red flickering and static test stimuli and report a clinical implementation of these stimuli in visual perimetry.
  
  
  METHODS
  The adaptation profile for red-on-white perimetry stimuli was measured using a threshold vs. intensity (TvI) paradigm at 0 degree and 12 degrees eccentricity and by comparing the eccentricity-related sensitivity change for red and white, static, and flickering targets in young normal trichromats (n = 5) and a group of dichromats (n = 5). A group of older normal control observers (n = 30) were tested and retinal disease was evaluated in persons having age-related maculopathy (n = 35) and diabetes (n = 12).
  
  
  RESULTS
  Adaptation and eccentricity profiles indicate red static and flickering targets are detected by two mechanisms in the paramacular region, and a single mechanism for >5 degrees eccentricity. The group data for the older normal observers has a high level of inter-observer variability with a generalized reduction in sensitivity across the entire visual field. Group data for the participants with age-related maculopathy show reduced sensitivities that were pronounced in the central retina. The group data for the diabetic observers showed sensitivities that were reduced at all eccentricities. The disease-related sensitivity decline was more apparent with red than white stimuli.
  
  
  CONCLUSIONS
  The adaptation profile and change in sensitivity with retinal eccentricity for the red-on-white perimetric stimuli are consistent with two detection processes. In the macula, the putative detection mechanism is color-opponent with static targets and non-opponent with flickering targets. At peripheral field locations, the putative detection mechanism is non-opponent for both static and flicker targets. The long-wavelength stimuli are less affected by the preretinal absorption common to aging. Red-on-white static and flicker perimetry may be useful for monitoring retinal disease, revealing greater abnormalities compared with conventional white-on-white perimetry, especially in the macula where two detection mechanisms are found.
authors.affiliation: Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, Victoria, Australia.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Zele
authors.forename: Trung M
authors.initials: TM
authors.lastname: Dang
authors.forename: Rebecca K
authors.initials: RK
authors.lastname: O'Loughlin
authors.forename: Robyn H
authors.initials: RH
authors.lastname: Guymer
authors.forename: Alex
authors.initials: A
authors.lastname: Harper
authors.forename: Algis J
authors.initials: AJ
authors.lastname: Vingrys
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D015331:Cohort Studies; D003118:Color Perception / Q000502:physiology*; D006801:Humans; D008875:Middle Aged; D015203:Reproducibility of Results; D012160:Retina / Q000502:physiology*; D012684:Sensory Thresholds; D014792:Visual Acuity; D058609:Visual Field Tests / Q000379:methods*; D014794:Visual Fields / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*