Abstract
Purpose :
To construct digital video fluorescein angiography camera to measure retinal blood flow by quantitatively analysis of angiography data.
Methods :
The camera was designed to take a fluorescein angiography movie at high frame rate of 20 fps over 50 degrees (°) of the fundus using the 4M pixels CMOS camera at the working distance of 17.0mm. After finely aligning of the all frames, intensity of the fluorescence signal measured in the fovea and macula was plotted in time sequence. We measured rising and falling coefficients of the fluorescence signal at the middle of the retinal artery and vein caliber by fitting two sigmoid functions to find the inflection points. The propagation velocity of the dye through the retinal artery was calculated by measuring the rising coefficients at different locations of the retinal vessel.
Results :
Optical and illumination simulation (Zemax®) showed that the radius of the Airy disk is 2.9μm at the center and 4.3μm at 50°. The illumination power of the retina was measured as 123.7μW. As a result of quantitative analysis, the signal from fovea showed little change during all periods. In case of macula, signals increased from the first 8.15 seconds(s) to 18.85s, then decreased and stabilized at 27.05s. Mean rising and falling coefficients of the retinal vessels originating from the optic disc were 10.91 ± 0.12s and 21.25 ± 0.37s in the arteries, and 13.86 ± 0.61s and 25.91 ± 0.87s in the veins, respectively. The dye propagation velocity was calculated as 6.80 ± 0.99 mm/s.
Conclusions :
Constructed digital video fluorescein angiography camera was able to quantitatively analyze the fluorescein signal as well as calculate the velocity of the dye propagating rapidly into the retinal artery. This equipment could be effective for understanding the fluid dynamics of the retinal vasculature.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.