title: Differential effect of long versus short wavelength light exposure on pupillary re-dilation in patients with outer retinal disease.
abstract: BACKGROUND
  In patients with outer retinal degeneration, a differential pupil response to long wavelength (red) versus short wavelength (blue) light stimulation has been previously observed. The goal of this study was to quantify differences in the pupillary re-dilation following exposure to red versus blue light in patients with outer retinal disease and compare them with patients with optic neuropathy and with healthy subjects.
  
  
  METHODS
  Prospective comparative cohort study.
  
  
  METHODS
  Twenty-three patients with outer retinal disease, 13 patients with optic neuropathy and 14 normal subjects.
  
  
  METHODS
  Subjects were tested using continuous red and blue light stimulation at three intensities (1, 10 and 100 cd/m2) for 13 s per intensity. Pupillary re-dilation dynamics following the brightest intensity was analysed and compared between the three groups.
  
  
  METHODS
  The parameters of pupil re-dilation used in this study were: time to recover 90% of baseline size; mean pupil size at early and late phases of re-dilation; and differential re-dilation time for blue versus red light.
  
  
  RESULTS
  Patients with outer retinal disease showed a pupil that tended to stay smaller after light termination and thus had a longer time to recovery. The differential re-dilation time was significantly greater in patients with outer retinal disease (median = 28.0 s, P < 0.0001) compared with controls and patients with optic neuropathy.
  
  
  CONCLUSIONS
  A differential response of pupil re-dilation following red versus blue light stimulation is present in patients with outer retinal disease but is not found in normal eyes or among patients with visual loss from optic neuropathy.
authors: Hôpital Ophtalmique Jules Gonin, University of Lausanne, Lausanne, Switzerland.
authors: Lorette
authors: L
authors: Léon
authors: Sylvain V
authors: SV
authors: Crippa
authors: François-Xavier
authors: FX
authors: Borruat
authors: Aki
authors: A
authors: Kawasaki
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D005260:Female; D006801:Humans; D008027:Light; D008297:Male; D008875:Middle Aged; D009901:Optic Nerve Diseases / Q000503:physiopathology; D010775:Photic Stimulation; D011446:Prospective Studies; D011680:Pupil / Q000528:radiation effects*; D012025:Reflex, Pupillary / Q000502:physiology*; D012162:Retinal Degeneration / Q000503:physiopathology*; D058609:Visual Field Tests; D014794:Visual Fields / Q000502:physiology