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R. Praga, M. Klemm, D. Hufnagel, L. Wagenfeld, P. Galambos, N. Matthiesen, A. Wiermann, G. Richard, O. Zeitz; Dynamic Color Doppler Imaging (dCDI): Effect of Flicker Stimulation on the Blood Flow Velocities in the Retrobulbar Central Retinal Artery in Healthy Volunteers. Invest. Ophthalmol. Vis. Sci. 2007;48(13):2260.
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© ARVO (1962-2015); The Authors (2016-present)
Several ocular diseases including glaucoma and diabetic retinopathy are associated with disturbed regulation of retinal perfusion. This might be visualized by combining methods assessing ocular hemodynamics with procedures challenging regulation of retinal perfusion. In the present study a combination of flicker light stimulation with color Doppler imaging (CDI) is introduced.
Seven healthy volunteers underwent color Doppler examination 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, 60s after and 120s after terminating the flicker stimulation. This cycle was repeated five times in each volunteer. For statistics an ANOVA model was applied.
EDV increased from 1.6±0.5 to 2.9±0.4 cms-1 in presence of flicker stimulation and decreased to 1.2±0.1 cms-1 at 120s after termination of flicker (P<0.05; n=7). PSV increased in tendency but statistically insignificant from 9.7±1.1 to 11.1±1.2 cms-1 in presence of flicker and returned to baseline after terminating the flicker (n.s.; n=7). These data are from the first cycle of measurements. Comparable results were obtained in the four other cycles. An individual evaluation of the effect of the five repeated flicker stimulation for each subject was done. A significant increase of EDV with P<0.008 was present in 6 of the 7 volunteers. In one male also PSV was significantly increased by flicker light stimulation.
The data from the present study show an enhancing effect of retinal flicker stimulation on retrobulbar blood flow velocities in healthy volunteers and it demonstrates the applicability of a combination of flicker stimulation and color Doppler imaging. The authors term this novel method dynamic Color Doppler imaging (dCDI). dCDI may widen the diagnostic spectrum of CDI and future studies are needed to elucidate the diagnostic power of dCDI.
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