Abstract

The non-invasive measurement of retinal blood flow changes can provide a unique method for monitoring vascular changes in diabetes and concomitant in vivo investigations into the biologic effects of various metabolic and vasoactive agents. A Video Fluorescein Angiography (VFA) system has been developed (1) and used to provide real time recordings of retinal fluorescein angiograms from a rat animal model. A low light level sensitive video camera was interfaced to a standard Nikon NFC-50 fundus camera fitted with a small pupil adaptor to facilitate better imaging of the retina through the smaller rat pupil. A silicon intensified target (Dage-MTI SIT-66) camera was used featuring low light level sensitivity and high resolution (700 video lines at 0.001 foot-candles). The gain of the image intensifier was controlled manually and for these experiments was set at 3 KV. At this gain setting and level of fundus camera illumination (1/3 of total useable intensity), the video signal did not saturate at arterial sites during VFA recording. The video images were recorded onto a high resolution monochrome optical disc recorder which facilitated a frame by frame digitization of the images.

© 1991 Optical Society of America