OCT technology has revolutionized how eyecare practitioners examine patients and manage disease. Simple thickness measurements of the macula and peripapillary retinal nerve fiber layer have evolved into sophisticated analyses of the retina, ganglion cells, optic nerve and anterior segment. Now optical coherence tomography angiography (OCT-A) opens a whole new ophthalmic frontier with noninvasive imaging of the retinal and choroidal vasculature.
OCT-A takes advantage of motion-based variance within sequential OCT images to create captures high-resolution images of retinal and choroidal vasculature. Each OCT scan is repeated up to four times in rapid succession at the same location. Because retinal tissue doesn’t move over the course of a few milliseconds, the only difference between the four scans should be the movement of red blood cells within vessels. The location of moving red blood cells is then used to create vasculature images called OCT angiograms.