Retinal Vessel Analysis - New Possibilities

Abstract

Retinal Vessel Analysis is a new technique to assess behavior of large retinal vessels based on diameter measurements. The Retinal Vessel Analyzer (RVA) measures continuously on-line obtaining data in relation to time and local position. Possible analysis tools include (a) Time Course Analysis of physiological, pathological, or therapy induced changes; (b) Local Course Analysis to recognize local narrow or wide vessel segments along the vessel; (c) Vasomotoric Analysis to determine vasomotions and blood pressure related diameter changes; (d) Functional Analysis to examine dynamic behavior e.g. the ability to autoregulate and (e) Functional Imaging to visualize functional parameters of vessels in single vessel segments. RVA is thus able to recognize and study different autoregulation mechanisms.

Dynamics of retinal vessel response to flicker light in glaucoma patients and ocular hypertensives

“…Details on the device and its application have been published previously [4,5,7,16]. In short, this device consists of a fundus camera (FF450, Zeiss Jena, Germany) for the examination and recording of the ocular fundus, and the RVA control computer which allows continuous as well as offline readings of the retinal vessel diameter.…”

“…The term neurovascular coupling refers to a rapid response of neural tissue blood vessels to increased neuronal activity, and it has recently been investigated in glaucoma patients and patients with ocular hypertension [2,3]. Optical accessibility of the retinal vessels and the light sensitivity of the retinal neural circuitry make the use of the Retinal Vessel Analyzer (RVA; IMEDOS GmbH, Weimar, Germany) particularly appealing in this field of research [4][5][6]. Recently, specific protocols for the use of this device have been discussed and published [7], as well as data on technical (measurement error) and biological (variability of vessel response to flickering light) reproducibility [8,9].…”

The Time Course of Changes in Retinal Vessel Diameter in Response to Differing Durations of Flicker Light Provocation

“…After full pupil dilation was reached with 1% tropicamide (Chauvin Pharmaceuticals Ltd., Kingston-Upon-Thames, UK), vessel diameters of retinal arteries and veins were obtained using the Retinal Vessel Analyser (RVA; Imedos Systems, Jena, Germany). 20 In brief, retinal vessel diameters in the patient's preferred eye were measured continuously at a sampling rate of 25 Hz. Stimulation of retinal blood vessels occurred through optoelectronic interruption of the green fundus illumination used by the RVA resulting in a FL provocation of 12.5 Hz.…”

Insulin is a key determinant of elevated retinal arteriolar flicker response in insulin-resistant individuals

“…Retinal vascular imaging Following mydriasis of the right pupil by 1% tropicamide eye drops, the mean diameter of a retinal arterial and venous segment was continuously measured in relation to time and position using the Dynamic Vessel Analyzer (DVA; Imedos, Jena, Germany) [13]. Vessel segments of approximately 1.5 mm in length located between one and two disc diameters from the margin of the optic disc edge were examined in continuous light for 30 s followed by three cycles of 20 s flicker-light provocation only interrupted by 50 s of steady fundus illumination.…”