title: Sites of cone system sensitivity loss in retinitis pigmentosa.
abstract: OBJECTIVE
  To examine the sites of cone sensitivity loss in patients with retinitis pigmentosa by comparing focal electroretinographic and psychophysical modulation thresholds.
  
  
  METHODS
  Both psychophysical and electrophysiologic increment threshold curves were obtained in retinitis pigmentosa patients and a group of age-matched, normally-sighted adults.
  
  
  RESULTS
  The majority of the retinitis pigmentosa data could be accounted for by a vertical displacement of the normal curve. The retinitis pigmentosa patients showed similar patterns of cone sensitivity losses using both techniques.
  
  
  CONCLUSIONS
  The combined electrophysiologic and psychophysical results provide support for an outer retina locus for these cone sensitivity losses. The data suggest that these deficits may be caused by a spatially independent loss of cone photoreceptors with normal adaptation properties in the remaining photoreceptors.
authors.affiliation: Department of Ophthalmology, New York University Medical Center, NY 10016.
authors.forename: W H
authors.initials: WH
authors.lastname: Seiple
authors.forename: K
authors.initials: K
authors.lastname: Holopigian
authors.forename: V C
authors.initials: VC
authors.lastname: Greenstein
authors.forename: D C
authors.initials: DC
authors.lastname: Hood
mesh_terms: D000221:Adaptation, Ocular; D000328:Adult; D004596:Electroretinography; D006801:Humans; D008027:Light; D008875:Middle Aged; D010786:Photoreceptor Cells / Q000502:physiology*; D011601:Psychophysics; D012174:Retinitis Pigmentosa / Q000503:physiopathology*; D012684:Sensory Thresholds