title: [The myogenic response of retinal arterioles in diabetic retinopathy].
abstract: OBJECTIVE
  The retinal vessel analyzer (RVA) offers the unique opportunity for noninvasive online measurements of the "Bayliss effect." In the presented study this myogenic response is used to test vessel contractility of retinal arterioles in different stages of diabetic retinopathy (DR).
  
  
  METHODS
  Forty patients with diabetes were exposed to a standardized rise in blood pressure. The myogenic response of a retinal arteriole was measured by continuous use of the RVA during this time. The subjects were divided into four groups (each n=10) according to different stages of DR. Group I: no DR, group II: mild/moderate DR, group III: moderate/severe nonproliferative DR with laser treatment, and group IV: proliferative DR with laser treatment.
  
  
  RESULTS
  A similar blood pressure rise was achieved in all subjects. In response to this BP rise, group I demonstrated a vasoconstriction of -7.6% (+/-4.1). In group II -0.85% (+/-4.3) and in group III a mild vasodilation of +0.44% (+/-5.9) was found. Group IV presented a vasodilatation of +3.2% (+/-5.9).
  
  
  CONCLUSIONS
  According to the progression of the morphological changes in diabetic retinopathy a functional deficit in the autoregulation of retinal arterioles can be measured with the RVA.
authors.affiliation: Augenklinik, Helios Klinikum, Nordhäuser Strasse 74, 99089 Erfurt. mblum@erfurt.helios-kliniken.de
authors.forename: M
authors.initials: M
authors.lastname: Blum
authors.forename: C
authors.initials: C
authors.lastname: Pils
authors.forename: U A
authors.initials: UA
authors.lastname: Müller
authors.forename: J
authors.initials: J
authors.lastname: Strobel
mesh_terms: D001794:Blood Pressure; D003930:Diabetic Retinopathy / Q000473:pathology* / Q000503:physiopathology*; D005260:Female; D006487:Hemostasis; D006801:Humans; D008297:Male; D008833:Microcirculation / Q000473:pathology* / Q000503:physiopathology*; D008875:Middle Aged; D009131:Muscle, Smooth, Vascular / Q000503:physiopathology; D012161:Retinal Artery / Q000473:pathology* / Q000503:physiopathology*; D042262:Retinoscopy / Q000379:methods; D014664:Vasodilation