title: [Comparison of diameter response of retinal arteries and veins to flickering light. A clinical study with healthy people].
abstract: OBJECTIVE
  The aim of this study was to compare the diameter response of retinal arteries and veins after provocation with flickering light regarding the amplitude and temporal course.
  
  
  METHODS
  The study included 26 healthy volunteers. The vessel diameter was automatically and continuously measured by the retinal vessel analyzer. The examination consisted of a baseline measurement (100 s) followed by five periods of 20-s flicker light provocation and 80-s follow-up observation.
  
  
  RESULTS
  A diameter dilation was observed immediately after the end of the flicker period in arteries (6.9+/-2.8%) and veins (6.5+/-2.8%, difference n.s.). The quotient of arterial and venous dilation (AVDQ) was 1.25+/-0.69 (range: 0.2-2.8). A significant correlation of age and arterial or venous dilation or the AVDQ was not observed. The arterial diameter reduced faster than the venous and reached a minimum of -2.7+/-1.4% at 25.9+/-10.8 s after the end of the flicker phase. The veins were dilated by 0.5+/-1.3% at the time of the maximal individual arterial constriction (p<0.0001).
  
  
  CONCLUSIONS
  Flicker-evoked response of retinal arteries and veins did not differ in the dilative amplitude but in the temporal course of the abatement of the dilation.
authors.affiliation: Augenarztpraxis, Rudolstadt. e_a_nagel@t-online.de
authors.forename: E
authors.initials: E
authors.lastname: Nagel
authors.forename: W
authors.initials: W
authors.lastname: Vilser
authors.forename: I
authors.initials: I
authors.lastname: Lanzl
mesh_terms: D000328:Adult; D000368:Aged; D019412:Anatomy, Cross-Sectional / Q000379:methods*; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008027:Light; D008297:Male; D008875:Middle Aged; D010775:Photic Stimulation / Q000379:methods*; D012161:Retinal Artery / Q000033:anatomy & histology / Q000502:physiology* / Q000528:radiation effects; D012169:Retinal Vein / Q000033:anatomy & histology / Q000502:physiology* / Q000528:radiation effects; D014664:Vasodilation / Q000502:physiology* / Q000528:radiation effects