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Sanam Mozaffari, Fabio Feroldi, Francesco LaRocca, Pavan K. Tiruveedhula, Patrick Gregory, B. Hyle Park, Austin John Roorda; Actively stabilized AOOCT with independent focus adjustment for optimal AOSLO-based eye tracking. Invest. Ophthalmol. Vis. Sci. 2021;62(8):10.
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To demonstrate optimal strategies for structural imaging of the human retina with an adaptive optics optical coherence tomography (AOOCT) system guided with real-time eye tracking signals from an adaptive optics scanning laser ophthalmoscope (AOSLO).
A 1040 nm swept source OCT system was coaligned with an AOSLO system via a dichroic mirror placed prior the deformable mirror such that the OCT 7.2 mm beam size would benefit from the adaptive optics correction. Independent AOOCT focus-adjustment was implemented with a set of fold mirrors on a motorized stage to adjust the distance between one of the telescopes in the sample arm of the OCT path. A second motorized stage was used in the reference arm to match the path length and maintain the interference signal. Eye position reported from the AOSLO with cellular resolution and at a frequency of 960 Hz was used to drive a 2D scanner in the AOOCT path to compensate for eye motion in real time. The purpose for independent focus control was to allow the AOOCT to be optimally focused on a retinal layer of interest while the AOSLO maintained focus on the photoreceptor layer, which offers rich texture and high signal-to-noise for accurate, high-speed tracking. AOSLO and AOOCT videos were recorded in sync such that each AOSLO frame corresponded to four AOOCT B-scans acquired at 120Hz. Volumes were acquired from two subjects, in which the AOOCT focus was adjusted through the retinal layers.
We successfully implemented actively stabilized AOOCT with independent focus adjustment to image different layers in the retina while maintaining high fidelity active eye motion tracking using the AOSLO locked onto the photoreceptor mosaic. Since the eye motion was corrected in real time using the same spatial reference, the volumes required minimal processing and could be averaged within the entire imaging session over multiple acquisitions with no lateral registration.
We have implemented an AOOCT system with active eye tracking that has full control for focus-optimized targeted imaging in 3 dimensions. The AOOCT offers high throughput as individual volume images require no distortion correction or lateral registration between separate imaging sessions. This is the first step in building a platform technology that will be used for a range of applications including visual psychophysics, clinical applications and measuring the optoretinogram.
This is a 2021 ARVO Annual Meeting abstract.
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