AJP - Heart and Circulatory Physiology, Vol 234, Issue 3 315-H322, Copyright © 1978 by American Physiological Society
Fluorescein dye-dilution technique and retinal circulation
C. E. Riva, G. T. Feke and I. Ben-Sira
Using theoretical models for the flow of fluourescein dye in retinal
arteries and veins, we have determined the effects of optical absorption in
blood of the incident excitation light and the emitted fluorescent light on
the time course of measured fluorescence intensity, I(t). Our results
indicate that I(t) curves recorded from arteries adequately represent the
mean time course of the fluorescein concentration (C(t)), when either a
circular or rectangular light-collecting aperture is used. I(t) curves
recorded from veins adequately represent C(t), but only when a circular
aperture of approximately the same diameter as that of the vessel is used.
A two-point fluorophotometer, which provides simultaneous, on-line
measurements of arterial and venous I(t) curves is described. Typical
recordings obtained with the instrument are shown and the method employed
to analyze the curves quantitatively is described in detail. This method,
which consists of fitting the first passage of the fluorescence intensity
curve with a log-normal function, provides results that are more accurate
than those obtained using the standard exponential extrapolation method.
