Abstract
Purpose::
To measure total retina blood flow.
Methods::
A Fourier-domain Doppler optical coherence tomography (FD-DOCT) system with an axial resolution of 4.6 µm, frame rate of 5.8 frames/second and minimal detectable Doppler shift of 51 Hz (0.016 mm/s) was used. We used a dual-plane scanning pattern to determine the angle between the blood vessel and the scanning beam in order to measure total flow velocity. Volumetric flow in each blood vessel around the optic nerve head was integrated in one cardiac cycle in each measurement. Measurements were performed in the right eye of one human subject.
Results::
Normal human volumetric retinal flow was measured in vivo. Based on their different flow directions, arteries can be distinguished from veins. The measured venous flow velocity ranged from 16.3 mm/s to 29.7 mm/s. The arterial flow velocity ranged from 38.4 mm/s to 78.2 mm/s. The total retinal venous and arterial flow both added up to approximately 54 µl/minute.
Conclusions::
We describe the first OCT measurement of total retinal blood flow averaged over the cardiac cycle. Unlike other methods for retinal blow flow measurement, our technique did not require any assumptions on vessel geometry, flow profile or any other anatomic and flow parameters. Thus the measurements are absolute and may improve the detection of abnormal increase or decrease in retinal perfusion. A fast scanning pattern will be developed for quick assessment of retinal flow based on this technique.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • blood supply • image processing