Variability of perifoveal microcirculation in healthy probands

Abstract

Fluorescein angiography with a scanning laser ophthalmoscope allows the assessment of retinal hemodynamics. Fundamental for all interpretations of the evaluated data is the knowledge of the physiological variation. In the present study we examined the variability of dynamic and morphologic retinal blood flow indices in healthy subjects over a period of one year. In sixteen healthy volunteers aged from 23 to 34 years video-fluorescein angiography was repeated nine times in one year. At each term arm-retina-time, arteriovenous passage time, mean arterial dye velocity and capillary flow velocity were assessed. In addition the perifoveal intercapillary areas and the foveal avascular zone were determined at the first and last examination. Statistical analysis of the evaluated data did not show any significant variation of the mean values during the one year follow-up. Reliability indices between 0.61 and 0.87 underline a stable position of each subject to the other participants at the single terms. The present study demonstrates that retinal hemodynamics are stable over a one year follow-up in healthy subjects. There are not significant changes to expect in retinal hemodynamics assesses in healthy subjects in one year under constant conditions. The knowledge of the intra- and interindividual variation of retinal blood flow indices allows a correct interpretation of pathophysiologic and pharmacological changes in retinal macro- and microcirculation.