Three-dimensional quantitative imaging of retinal and choroidal blood flow velocity using joint Spectral and Time domain Optical Coherence Tomography

Recently, joint Spectral and Time domain Optical Coherence Tomography (joint STdOCT) has been proposed to measure ocular blood flow velocity. Limitations of CCD technology allowed only for two-dimensional imaging at that time. In this paper we demonstrate fast three-dimensional STdOCT based on ultrahigh speed CMOS camera. Proposed method is straightforward, fully automatic and does not require any advanced image processing techniques. Three-dimensional distributions of axial velocity components of the blood in human eye vasculature are presented: in retinal and, for the first time, in choroidal layer. Different factors that affect quality of velocity images are discussed. Additionally, the quantitative measurement allows to observe a new interesting optical phenomenon - random Doppler shift in OCT signals that forms a vascular pattern at the depth of sclera.