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Kate Grieve, Jules Scholler, Kassandra Groux, Yao Cai, Michel Paques, Claude Boccara, Pedro Mecê; High-resolution retinal imaging over a large field-of-view with adaptive-glasses Full-Field OCT . Invest. Ophthalmol. Vis. Sci. 2021;62(11):40.
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© ARVO (1962-2015); The Authors (2016-present)
We introduce Adaptive-Glasses Full-Field OCT (FFOCT), a retinal imaging system allying high-resolution, high frame rate (300Hz), and 5° FOV in a compact system (footprint: 30cmX50cm).
Retinal imaging was performed over a region stretching from 12N to 5T in five healthy volunteer subjects. Our retinal imager combines a time-domain FFOCT and an SDOCT, enabling correction of axial eye motion in real-time. We previously demonstrated the capacity of this system to achieve foveal cone mosaic imaging without the use of AO, owing to the low sensitivity to ocular aberrations of FFOCT when using spatially incoherent light. Aberrations were shown to decrease the signal to noise ratio (SNR) but not the resolution. To increase the SNR, we implemented a lens-based sensorless AO approach using a multi-actuator adaptive lens (MAL) positioned in front of the eye, like prescribed eyeglasses, in a technique we call the adaptive-glasses approach. The SDOCT signal was used as a merit function for the wavefront optimization. Cones were quantified by measuring the spatial frequency of the Yellot’s ring at each eccentricity, and display was color coded for density.
The FFOCT SNR was enhanced up to a factor of 10 by using the MAL for a dilated pupil. The MAL can adjust the focus axial position within the retina, to image structures in the inner retina such as the nerve fiber layer with an 8 µm axial resolution. Moreover, owing to the combination of FFOCT with the adaptive-glasses approach, we can acquire high-resolution FFOCT images over a 5° FOV, without apparent anisoplanatism. IS/OS and COST layers could be distinguished and quantified from 12N to 5T with only a 5 image montage, representing a 2.5 second acquisition time. Cones were resolved to within 0.5° of the foveal center, with densities in agreement with the literature.
We showed that the combination of FFOCT, which presents a weaker sensitivity to symmetric aberrations in terms of lateral resolution, and the adaptive-glasses approach, to increase the SNR of FF-OCT image and to favor anisoplanatic correction, opens a new avenue to wide FOV high-resolution retinal imaging in a compact imaging system configuration, taking up essential challenges to facilitate clinical deployment of AO-OCT. The system is now installed at the Quinze Vingts National Ophthalmology Hospital in France for clinical trials in patients.
This is a 2021 Imaging in the Eye Conference abstract.
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