Current clinically available OCTA imaging methods are able to reliably distinguish retinal regions of significant flow from static tissue by evaluating the backscattered OCT signal from repeated measurements. By accurately controlling time delay and position offset between repeated acquisitions, quantitative OCT-based measurements of the underlying blood flow velocity and flow rate are additionally enabled. Multiple methods have been developed for this purpose that operate either on phase, amplitude, or the complex OCT signal and, accordingly, build on different physical models for interpreting the OCT signal modulation arising from moving red blood cells. Here, we present an overview of the technical background of OCT-based methods for quantitative velocimetry, describe their application for retinal imaging in vivo, and discuss their potential and limitations for future clinical ophthalmic applications.
Copyright 2019, The Author(s).