Abstract

P 166

Dynamic Color-Doppler-Imaging (dCDI): Changes of retrobulbar hemodynamics induced by flicker stimulation of the retina

Zeitz O., Hufnagel D., Praga R., Wagenfeld L., Galambos P., Wiermann A., Matthiesen N., Richard G., Klemm M.
Klinik und Poliklinik für Augenheilkunde, Universitätsklinikum Hamburg-Eppendorf

Objective: A stimulation of the retina by flicker light leads to changes of vascular tone and perfusion by metabolic regulation. This effect is utilized e.g. fort he retinal vessel analysis by the Retinal Vessel Analyzer (RVA). In the presented work it is aimed to investigate wether the flicker effect is also detectable in retrobulbar vessels examined by color Doppler imaging.
Methods: Healthy volunteers and glaucoma patients underwent color Doppler examination (Siemens Elegra; applicator 7.5L40 at 9.5MHz) of the central retinal artery. After recording of baseline peak systolic velocity (PSV) and end-diastolic velocity (EDV), the retina was stimulated by a 10 Hz flicker through the closed eye lids. CDI measurements were repeated after 15s of flicker stimulation, as well as immediately after, 1min after and 2min after terminating the flicker stimulation.
Results: Flicker stimulation leads to an increase of EDV from 1.8±0.3 to 2.6±0.4 cm/s (n=9;P<0.05) in healthy volunteers. The PSV shows an statistically insignificant slight increase from 9.0±0.9 to 10.3±1.0 cm/s (n=9;n.s.). One minute after the termination of the flicker light stimulation Doppler parameters have returned to baseline. In glaucoma patients no statistically significant change of PSV and EDV was detected by flicker stimulation (EDV: before flicker 1.1±0.3 vs. 1.9±0.3 cm/s during flicker; PSV: 8.3±0.9 vs. 8.8±0.8 cm/s; n=10; n.s. für EDV und PSV).
Conclusions: The flicker induced retinal vasodilation leads to detectable changes in retrobulbar hemodynamics. In this preliminary case series a difference between glaucoma patients and healthy volunteers is on horizon. Die dCDI method might be an alternative to RVA measurements e.g. in patients with hazy optic media

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