High-speed, digitally refocused retinal imaging with line-field parallel swept source OCT

Daniel J. Fechtig; Abhishek Kumar; Laurin Ginner; Wolfgang Drexler; Rainer A. Leitgeb

doi:10.1117/12.2081924

2 March 2015 High-speed, digitally refocused retinal imaging with line-field parallel swept source OCT

Daniel J. Fechtig, Abhishek Kumar, Laurin Ginner, Wolfgang Drexler, Rainer A. Leitgeb

Proceedings Volume 9312, Optical Coherence Tomography and Coherence Domain Optical Methods in Biomedicine XIX; 931203 (2015) https://doi.org/10.1117/12.2081924
Event: SPIE BiOS, 2015, San Francisco, California, United States

Abstract

MHz OCT allows mitigating undesired influence of motion artifacts during retinal assessment, but comes in state-of-the-art point scanning OCT at the price of increased system complexity. By changing the paradigm from scanning to parallel OCT for in vivo retinal imaging the three-dimensional (3D) acquisition time is reduced without a trade-off between speed, sensitivity and technological requirements. Furthermore, the intrinsic phase stability allows for applying digital refocusing methods increasing the in-focus imaging depth range. Line field parallel interferometric imaging (LPSI) is utilizing a commercially available swept source, a single-axis galvo-scanner and a line scan camera for recording 3D data with up to 1MHz A-scan rate. Besides line-focus illumination and parallel detection, we mitigate the necessity for high-speed sensor and laser technology by holographic full-range imaging, which allows for increasing the imaging speed by low sampling of the optical spectrum. High B-scan rates up to 1kHz further allow for implementation of lable-free optical angiography in 3D by calculating the inter B-scan speckle variance. We achieve a detection sensitivity of 93.5 (96.5) dB at an equivalent A-scan rate of 1 (0.6) MHz and present 3D in vivo retinal structural and functional imaging utilizing digital refocusing. Our results demonstrate for the first time competitive imaging sensitivity, resolution and speed with a parallel OCT modality. LPSI is in fact currently the fastest OCT device applied to retinal imaging and operating at a central wavelength window around 800 nm with a detection sensitivity of higher than 93.5 dB.

Citation Download Citation

Daniel J. Fechtig, Abhishek Kumar, Laurin Ginner, Wolfgang Drexler, and Rainer A. Leitgeb "High-speed, digitally refocused retinal imaging with line-field parallel swept source OCT", Proc. SPIE 9312, Optical Coherence Tomography and Coherence Domain Optical Methods in Biomedicine XIX, 931203 (2 March 2015); https://doi.org/10.1117/12.2081924

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