title: [Response of retinal vessel diameter to flicker-light in vasospastics compared to healthy controls].
abstract: BACKGROUND
  Vascular dysregulation is considered to be a risk factor in several ophthalmic diseases. The purpose of this study was to evaluate the reaction of retinal vessels to flicker light in otherwise healthy subjects with a vasospastic propensity.
  
  
  METHODS
  Thirty healthy Caucasians, aged between 18-35 years were recruited for this study and grouped into vasospastics, based on a history of frequent cold hands, even in summer, with concordant findings in nailfold capillary microscopy, or as controls, if such a history was absent. The reaction of the retinal vascular diameter to flicker light was observed in a distance of two to three discs diameters away from the optic nerve head with the retinal vessel analyser. Three phases of flicker light of twenty seconds followed by baseline light phases of eighty seconds were recorded. The maximal vasodilatory amplitude of each flicker phase was determined and the results averaged.
  
  
  RESULTS
  The maximal average dilatory amplitude at the arterial side reached (mean +/- SD) 2.9 +/- 1.7 % and 4.8 +/- 2.6 % of the baseline amplitude respectively in vasospastic subjects and in healthy controls (t = 2.34; p = 0.025). The reaction at the venous side was statistically comparable in both groups.
  
  
  CONCLUSIONS
  Otherwise healthy, vasospastic subject disclosed an altered reaction of the retinal vasculature to flicker light in this study.
authors.affiliation: Universitätsspital Basel, Abteilung Ophthalmologie, Schweiz.
authors.forename: I
authors.initials: I
authors.lastname: Rickenbacher
authors.forename: K
authors.initials: K
authors.lastname: Gugleta
authors.forename: C
authors.initials: C
authors.lastname: Zawinka
authors.forename: A
authors.initials: A
authors.lastname: Schötzau
authors.forename: R
authors.initials: R
authors.lastname: Katamay
authors.forename: J
authors.initials: J
authors.lastname: Flammer
authors.forename: S
authors.initials: S
authors.lastname: Orgül
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D010775:Photic Stimulation / Q000379:methods*; D012171:Retinal Vessels / Q000473:pathology* / Q000528:radiation effects; D020301:Vasospasm, Intracranial / Q000175:diagnosis* / Q000473:pathology*; D055815:Young Adult