Abstract
Purpose: :
To evaluate retinal blood flow and to asses topological and dimensional properties of retinal microcirculation in healthy subjects and systemic hypertensive patients.
Methods: :
A prospective cross-sectional study. Twenty healthy volunteers subjects and sixteen nondiabetic patients with essential systemic hypertension were examined. Retinal blood flow was assessed by the Heidelberg Retina Flowmeter (HRF; Heidelberg Engeineering, Heildenberg, Germany) by using AFFPIA (automatic full field perfusion image analyzer) program; retinal blood flow and microvascular retinal network of normotensive and systemic hypertensive patients were compared. Basic and specific laboratory and instrumental evaluation was also performed for hypertensive patients and results were correlated with HRF measurements.
Results: :
Mean microvessel sizes were significantly lower in hypertensive patients than normal patients (23.09 ± 7.38 µm and 28.04 ± 8.22 µm, respectively; P < 0.01); microcrovessels between 40 and 50 µm size were higher (in percentage) in normal patients than in hypertensive patients (P < 0.01). No statistical difference was identifiable between the two groups for retinal blood flow.
Conclusions: :
Microvessel mean diameter, and possibly microvessel density, were reduced in hypertensive patients if compared to non-hypertensive patients. These data agree with previous histological and fluorangiographic studies and outline that < 100 µm size microvessels could be involved in the pathogenesis of essential hypertension. Further studies are needed to determine the usefulness of HRF, a totally non-invasive technique, in the clinical practice.
Keywords: retina • optic flow • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)