title: Cold pressor test and retinal capillary perfusion in vasospastic subjects with and without capsular glaucoma (a preliminary study).
abstract: OBJECTIVE
  Using the cold pressor test the authors investigated the change in retinal and neuroretinal capillary perfusion in vasospastic patients suffering from capsular glaucoma (CG) and in vasospastic control subjects.
  
  
  METHODS
  Changes in retinal and optic nerve head capillary perfusion induced by the cold pressor test (one hand immersed in 4 degrees C water for 30 seconds, then in 30 degrees C water for 2 minutes) was measured using the Heidelberg Retina Flowmeter in 4 patients with CG and in 5 healthy control subjects. Previously all subjects showed a reduction of cutaneous capillary flow higher than 70% in the cold pressor test (vasospastic reaction). One eye per subject was investigated. Two images were obtained for each phase (baseline, cold phase and warm phase), and the better quality image from each phase was selected for the measurements. One location on the temporal neuroretinal rim and one location on the temporal retina outside the peripapillary area were selected for the HRF measurements.
  
  
  RESULTS
  In the CG group neuroretinal rim "Volume" decreased by 26.05%, "Flow" by 25.82% and "Velocity" by 23.91% (p<0.05), retinal "Volume" decreased by 12.30% (p=0.051), and retinal "Flow" by 22.36% (p=0.01) in the cold phase. All these parameters returned to the corresponding baseline values in the warm phase. In the control group a significant decrease was observed in retinal "Volume" (15.96%), "Flow" (17.81%), and "Velocity" (16.11%) in the cold phase (p<0.05), which diminished in the warm phase but remained still significant for "Flow" and "Velocity".
  
  
  CONCLUSIONS
  Cutaneous cold provocation can induce an immediate decrease in retinal and optic nerve head capillary perfusion at least in a part of the vasospastic subjects with or without capsular glaucoma. This decrease diminishes or disappears quickly when the hand is immersed in warm water. To evaluate the potential role of cold-induced retinal and optic nerve head vasoconstriction in the pathogenesis of capsular glaucoma further investigations are necessary since this reaction was also present in the vasospastic control subjects.
authors.affiliation: 1st Department of Ophthalmology, Semmelweis University Medical School, Budapest, Hungary. kotpet@szem1.sote.hu
authors.forename: P
authors.initials: P
authors.lastname: Kóthy
authors.forename: I
authors.initials: I
authors.lastname: Süveges
authors.forename: P
authors.initials: P
authors.lastname: Vargha
authors.forename: G
authors.initials: G
authors.lastname: Holló
mesh_terms: D000368:Aged; D001794:Blood Pressure / Q000502:physiology; D002196:Capillaries / Q000502:physiology; D003080:Cold Temperature; D017889:Exfoliation Syndrome / Q000503:physiopathology*; D005260:Female; D006801:Humans; D017078:Laser-Doppler Flowmetry; D008297:Male; D008875:Middle Aged; D011312:Pressure; D012039:Regional Blood Flow / Q000502:physiology; D012171:Retinal Vessels / Q000502:physiology*; D012867:Skin / Q000098:blood supply; D020301:Vasospasm, Intracranial / Q000503:physiopathology*