Retinal vessel analysis
: flicker reproducibility, methodological standardisations and practical limitations

  • Angelos Kalitzeos

Student thesis: Doctoral ThesisDoctor of Philosophy


The Retinal Vessel Analyser (RVA) is a commercially available ophthalmoscopic instrument capable of acquiring vessel diameter fluctuations in real time and in high temporal resolution.
Visual stimulation by means of flickering light is a unique exploration tool of neurovascular
coupling in the human retina. Vessel reactivity as mediated by local vascular endothelial vasodilators and vasoconstrictors can be assessed non-invasively, in vivo. In brief, the work in
this thesis
• deals with interobserver and intraobserver reproducibility of the flicker responses in healthy volunteers
• explains the superiority of individually analysed reactivity parameters over vendorgenerated
• links in static retinal measures with dynamic ones
• highlights practical limitations in the use of the RVA that may undermine its clinical
• provides recommendations for standardising measurements in terms of vessel location
and vessel segment length and
• presents three case reports of essential hypertensives in a -year follow-up.
Strict standardisation of measurement procedures is a necessity when utilising the RVA system.
Agreement between research groups on implemented protocols needs to be met, before it could
be considered a clinically useful tool in detecting or predicting microvascular dysfunction.
Date of Award12 Mar 2014
Original languageEnglish
SupervisorRebekka Heitmar (Supervisor)


  • Cardiovascular Disease
  • Autoregulation
  • Blood Pressure
  • Endothelial Function

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