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Proceedings Paper

Structural and functional human retinal imaging with a fiber-based visible light OCT ophthalmoscope (Conference Presentation)
Author(s): Shau Poh Chong; Marcel T. Bernucci; Dawid Borycki; Harsha Radhakrishnan; Vivek J. Srinivasan

Paper Abstract

Visible light is absorbed by intrinsic chromophores such as photopigment, melanin, and hemoglobin, and scattered by subcellular structures, all of which are potential retinal disease biomarkers. Recently, high-resolution quantitative measurement and mapping of hemoglobin concentrations was demonstrated using visible light Optical Coherence Tomography (OCT). Yet, most high-resolution visible light OCT systems adopt free-space, or bulk, optical setups, which could limit clinical applications. Here, the construction of a multi-functional fiber-optic OCT system for human retinal imaging with <2.5 micron axial resolution is described. A detailed noise characterization of two supercontinuum light sources with differing pulse repetition rates is presented. The higher repetition rate, lower noise, source is found to enable a sensitivity of 87 dB with 0.1 mW incident power at the cornea and a 98 microsecond exposure time. Using a broadband, asymmetric, fused single-mode fiber coupler designed for visible wavelengths, the sample arm is integrated into an ophthalmoscope platform, rendering it portable and suitable for clinical use. In vivo anatomical, Doppler, and spectroscopic imaging of the human retina is further demonstrated using a single oversampled B-scan. For spectroscopic fitting of oxyhemoglobin (HbO2) and deoxyhemoglobin (Hb) content in the retinal vessels, a noise bias-corrected absorbance spectrum is estimated using a sliding short-time Fourier transform of the complex OCT signal and fit using a model of light absorption and scattering. This yielded path length (L) times molar concentration, LCHbO2 and LCHb. Based on these results, we conclude that high-resolution visible light OCT has potential for depth-resolved functional imaging of the eye.

Paper Details

Date Published: 19 April 2017
PDF: 1 pages
Proc. SPIE 10053, Optical Coherence Tomography and Coherence Domain Optical Methods in Biomedicine XXI, 100530H (19 April 2017); doi: 10.1117/12.2254934
Show Author Affiliations
Shau Poh Chong, Univ. of California, Davis (United States)
Marcel T. Bernucci, Univ. of California, Davis (United States)
Dawid Borycki, Univ. of California, Davis (United States)
Harsha Radhakrishnan, Univ. of California, Davis (United States)
Vivek J. Srinivasan, Univ. of California, Davis (United States)

Published in SPIE Proceedings Vol. 10053:
Optical Coherence Tomography and Coherence Domain Optical Methods in Biomedicine XXI
James G. Fujimoto; Joseph A. Izatt; Valery V. Tuchin, Editor(s)

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