title: The age-dependent decrease in the myogenic response of retinal arterioles as studied with the Retinal Vessel Analyzer.
abstract: OBJECTIVE
  To study the age-dependent change in myogenic response of retinal arterioles.
  
  
  METHODS
  Fifty-one healthy volunteers with at least ten persons in each of the five age decades (I-V) between 20 and 69 years were subjected to diameter measurement of retinal arterioles using the Retinal Vessel Analyzer (RVA) during rest and during an increase in the systemic blood pressure when lifting hand weights. The transmural pressure in the retinal arterioles during the procedures was estimated from the blood pressure and the intraocular pressure and was compared to the accompanying diameter response.
  
  
  RESULTS
  The retinal arteriolar diameter showed a significant decrease as a function of increasing weight for the two younger age groups below the age of 40 years (P=0.007, group I, and P=0.049, group II), compatible with perfect autoregulation, whereas no such change was observed in persons above this age (P=0.41, 0.053, 0.29 for groups III-V, respectively).
  
  
  CONCLUSIONS
  Studies on autoregulation in retinal disease should consider the normal age-related decrease in diameter response of retinal arterioles when the blood pressure is changed.
authors.affiliation: Department of Ophthalmology, Arhus University Hospital, Nørrebrogade 44, 8000, Arhus C, Denmark. pj@dadlnet.dk
authors.forename: Peter
authors.initials: P
authors.lastname: Jeppesen
authors.forename: Pernille A
authors.initials: PA
authors.lastname: Gregersen
authors.forename: Toke
authors.initials: T
authors.lastname: Bek
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology*; D001160:Arterioles / Q000502:physiology; D001783:Blood Flow Velocity / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology*; D015444:Exercise / Q000502:physiology; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000295:instrumentation / Q000379:methods; D008297:Male; D008875:Middle Aged; D009131:Muscle, Smooth, Vascular / Q000502:physiology*; D012039:Regional Blood Flow / Q000502:physiology; D012161:Retinal Artery / Q000502:physiology*; D014661:Vasoconstriction / Q000502:physiology*