Visible light optical coherence tomography angiography (vis-OCTA) facilitates local microvascular oximetry in the human retina

• Published in: Biomedical optics express Vol. 11; no. 7; pp. 4037 - 4051
• Main Authors: Song, Weiye, Shao, Wenjun, Yi, Wei, Liu, Rongrong, Desai, Manishi, Ness, Steven, Yi, Ji
• Format: Journal Article
• Language: English
• Published: Optical Society of America 01-07-2020
• ISSN: 2156-7085; 2156-7085
• DOI: 10.1364/BOE.395843

We report herein the first visible light optical coherence tomography angiography (vis-OCTA) for human retinal imaging. Compared to the existing vis-OCT systems, we devised a spectrometer with a narrower bandwidth to increase the spectral power density for OCTA imaging, while retaining the major spectral contrast in the blood. We achieved a 100 kHz A-line rate, the fastest acquisition speed reported so far for human retinal vis-OCT. We rigorously optimized the imaging protocol such that a single acquisition took < 6 seconds with a field of view (FOV) of 3×7.8 mm 2 . The angiography enables accurate localization of microvasculature down to the capillary level and thus enables oximetry at vessels < 100 µm in diameter. We demonstrated microvascular hemoglobin oxygen saturation (sO 2 ) at the feeding and draining vessels at the perifoveal region. The longitudinal repeatability was assessed by < 5% coefficient of variation (CV). The unique capabilities of our vis-OCTA system may allow studies on the role of microvascular oxygen in various retinal pathologies.