October 2018
Spotlight Summary by Robert Zawadzki
Simple approach for aberration-corrected OCT imaging of the human retina
In the latest paper by Helge Sudkamp, the authors propose a very simple system allowing acquisition of retinal data with phase stability that is suitable for computational aberration correction (CAC). To achieve that, they've built on the previous successes of their research team led by Gereon Hüttmann in developing parallel optical coherence tomography (OCT) detection systems. In these OCT systems, also called full-field OCT, the whole image is acquired simultaneously without the need for any mechanical scanning. This allows for fast and phase stable measurement of the retina in the living human eye. What is very interesting, however, is the fact that full-field time-domain OCT systems (FF-TD-OCT), described in this paper, might offer an intriguing advantage over full-field Fourier-domain OCT systems (FF-FD-OCT). This finding might seem counterintuitive as the last 15 years of OCT development focused mainly on improving FD-OCT acquisition schemes, proving repeatedly its sensitivity and detection speed advantage over the TD-OCT. Nevertheless, in case of CAC for retinal imaging, FF-TD-OCT offers a clear advantage when only one depth plane in the retina is of interest (for example photoreceptor mosaic) and when imaging system complexity and costs must be considered.
Finally, in their implementation of the off-axis FF-TD-OCT, the authors go to the origins of cellular retinal imaging as their system resembles the first successful adaptive optics fundus camera developed by Liang, Williams, and Miller. Here, the hardware AO system is replaced by an OCT interferometer. The results, however, are similar to those achieved by AO-fundus cameras, namely images of the photoreceptor mosaic, with a clear advantage of the OA-FF-TD-OCT offering access to the phase of the detected signal. This access to phase information can open the door to the optophysiological probing of retinal function in vivo and in combination with CAC allow cellular resolution without the need for complex and costly AO hardware that has been slowing down translation of cellular resolution retinal imaging to the clinics.
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Finally, in their implementation of the off-axis FF-TD-OCT, the authors go to the origins of cellular retinal imaging as their system resembles the first successful adaptive optics fundus camera developed by Liang, Williams, and Miller. Here, the hardware AO system is replaced by an OCT interferometer. The results, however, are similar to those achieved by AO-fundus cameras, namely images of the photoreceptor mosaic, with a clear advantage of the OA-FF-TD-OCT offering access to the phase of the detected signal. This access to phase information can open the door to the optophysiological probing of retinal function in vivo and in combination with CAC allow cellular resolution without the need for complex and costly AO hardware that has been slowing down translation of cellular resolution retinal imaging to the clinics.
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Article Information
Simple approach for aberration-corrected OCT imaging of the human retina
Helge Sudkamp, Dierck Hillmann, Peter Koch, Malte vom Endt, Hendrik Spahr, Michael Münst, Clara Pfäffle, Reginald Birngruber, and Gereon Hüttmann
Opt. Lett. 43(17) 4224-4227 (2018) View: Abstract | HTML | PDF