Blood flow measurement and slow flow detection in retinal vessels with Joint Spectral and Time domain method in ultrahigh speed OCT

We present an application of the Joint Spectral and Time domain OCT (STdOCT) method for detection of wide range of flows in the retinal vessels. We utilized spectral/Fourier domain OCT (SOCT) technique for development of scan protocols for Doppler signal analysis. We performed retinal imaging in normal eyes using ultrahigh speed (200 000 axial scans/s) SOCT instrument with a CMOS camera. Various raster scan protocols were implemented for investigation of blood flow in the retina. Data analysis was performed using the method of joint Spectral and Time domain OCT (STdOCT). Detection of blood flow velocities ranging from several tens of mm/s to a fraction of mm/s was possible with scanning methods allowing for appropriate selection of time intervals between data taken for Doppler OCT analysis. Axial blood flow velocity measurement was possible in retinal vessels. Doppler OCT signal can be utilized as a contrast mechanism for visualization of retinal capillaries.