title: The Time Course of Changes in Retinal Vessel Diameter in Response to Differing Durations of Flicker Light Provocation.
abstract: OBJECTIVE
  To determine the response of retinal vessels to differing durations of flicker light (FL) stimulation.
  
  
  METHODS
  We recorded retinal arterial and venous vessel dilation to 12.5 Hz FL provocation of varying duration (5, 7, 10, and 20 seconds) in 12 healthy young individuals (age range, 26-45 years). All participants underwent a full ocular examination including IOP and blood pressure measurements.
  
  
  RESULTS
  Maximum dilation (MD) did not show a significant dependence on flicker duration in arteries, whereas maximum constriction (MC) did. In veins, however, MD significantly increased with flicker duration. Approximately 80% to 90% of MD in arteries is reached within 10 seconds of FL stimulation.
  
  
  CONCLUSIONS
  The vast majority of arterial dilatory capacity is reached within 10 seconds of FL stimulation even though venous dilation continues strongly. Since MC of arteries shows a significant dependence on flicker duration, measurements at two different durations can provide more information about the retinal vascular system than at a single flicker duration alone.
authors.forename: Rebekka
authors.initials: R
authors.lastname: Heitmar
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Summers
mesh_terms: D000328:Adult; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D008027:Light; D008297:Male; D008875:Middle Aged; D010775:Photic Stimulation / Q000379:methods*; D012161:Retinal Artery / Q000502:physiology* / Q000528:radiation effects; D012169:Retinal Vein / Q000502:physiology* / Q000528:radiation effects; D014664:Vasodilation / Q000502:physiology*