title: Blood pressure effects on retinal vessel diameter and flicker response: a 1.5-year follow-up.
abstract: OBJECTIVE
  The study examined the influence of individual blood pressure changes overtime on retinal vessel diameter and the latter's response to flicker light.
  
  
  METHODS
  The diameter of a retinal arterial and venous segment was measured continuously on-line with a Dynamic Vessel Analyzer in 20 patients twice (mean interval between examinations of 24 months). Eleven patients had no cardiovascular disease. Nine patients had arterial hypertension and were untreated at the time of the first measurement; at the time of the second measurement they were undergoing various antihypertensive therapies. Each test consisted of a 50-s baseline plus three 20-s periods of flicker stimulation followed by an 80-s period of observation. During the examinations the blood pressure was measured at 1-minute intervals.
  
  
  RESULTS
  In the hypertension group changes in the mean arterial blood pressure (MAP) correlated significantly with changes in the arterial baseline diameter (y = -0.1 - 0.37x, r =0.74, p (increase) <0.03). A comparison of the two measurements showed no such relationship in the group of cardiovascularly healthy subjects. The venous baseline and the arterial and venous flicker response did not change significantly in either group between the two measurements and showed no relationship to blood pressure changes.
  
  
  CONCLUSIONS
  In hypertensive subjects, long-term therapy-related changes in blood pressure induced a change in the arterial baseline by approximately +3.7 microm/-10 mmHg MAP. An influence of lowering MAP to the arterial flicker response could not be detected.
authors.affiliation: Technical University, Ilmenau, Germany. 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: A
authors.initials: A
authors.lastname: Fink
authors.forename: T
authors.initials: T
authors.lastname: Riemer
authors.forename: I
authors.initials: I
authors.lastname: Lanzl
mesh_terms: D000959:Antihypertensive Agents / Q000627:therapeutic use; D001794:Blood Pressure / Q000502:physiology*; D005260:Female; D005425:Flicker Fusion / Q000502:physiology*; D006801:Humans; D006973:Hypertension / Q000188:drug therapy / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012171:Retinal Vessels / Q000502:physiology*
chemical_list: D000959:Antihypertensive Agents