Abstract
Presentation Description :
Optical coherence tomographic angiography (OCTA) provides 3-dimensional information on the ocular circulation down to the capillary level. It is noninvasive, inexpensive, and could potentially provide quantitative metrics that serve as clinical trial endpoint for many ocular diseases.
In glaucoma, the vessel density in the peripapillary nerve fiber layer plexus and macular superficial vascular complex have been shown to have better correlation with visual field parameters than structural measures. OCTA can measure regional capillary density and focal capillary dropout (low perfusion area) in 4 separate retinal vascular plexuses. Thus it could be useful in assessing treatments that improve perfusion and arrest disease progression in a wide range of retinal, optic nerve, and neurodegenerative diseases.
OCTA can detect choroidal neovascularization (CNV) even before exudation occurs. CNV vessel area as measured by OCTA show regression and reopening between anti-VEGF injections. Similarly, OCTA can measure the extent to which flow in retinal neovascularization shutdown in response to treatment for proliferative diabetic retinopathy. Thus OCTA measurements could be a good metric to measure the extent and duration of treatment response in neovascular diseases.
OCTA measurements are sensitive to potential bias by signal strength, shadowing, and focusing. Furthermore, measurement in deeper layers could be influence by the flow projection artifact. Thus it is important to carefully optimize image quality at the clinical centers and employ image processing algorithms that reduce these bias and artifacts at the reading centers. This is an area of increasing awareness and progress.
The performance of OCTA hardware and software is rapidly improving. As OCTA parameters become standardized and validated, they have great potential to become important endpoints for clinical trials because ocular perfusion is so closely tied to visual function and disease progression in so many eye conditions.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.