Active eye motion correction for AOOCT guided by simultaneous AOSLO human retinal imaging

Abstract

Purpose : In conventional optical coherence tomography (OCT) the biggest hurdle in acquiring measurements from specific locations is eye motion. In this study we utilize an adaptive optics scanning laser ophthalmoscope (AOSLO) to track the eye motion and actively drive a tip-tilt scanner to stabilize an AOOCT beam in real-time on the human retina.

Methods : A 1050 nm, 100kHz, swept source OCT system was coaligned with an AOSLO system via a dichroic mirror placed prior the deformable mirror such that OCT would benefit from the adaptive optics correction of the aberrations of the eye. The beam size at the pupil for the AOOCT path was 7.2 mm to ensure maximum resolution and signal collection. Eye position reported from the AOSLO with cellular resolution and at a frequency of 960 Hz was used to drive a tip/tilt scanner in the OCT to compensate for eye motion in real time. The tip/tilt scanner was also used to scan the beam, resulting in a B-scan that was stabilized on the retina. AOSLO and AOOCT videos were recorded in sync such that each SLO frame corresponded to one AOOCT B-scan acquired at 30Hz. The motion correction accuracy was experimentally tested with a moving model eye and retinal images were recorded for one healthy subject.

Results : We successfully implemented active eye motion correction for AOOCT to stabilize the high amplitude and low frequency drifts of both the model and human eye. Motion compensation steadily decreased with higher frequency movement, primarily due to technical limitations of the tip-tilt scanner. Nevertheless, when applied to a human eye the majority of the eye motion was effectively compensated. We can record cellular resolution B-scans from a fixed retinal location over long periods of time.

Conclusions : We demonstrate a system capable of recording high-resolution AOOCT video from targeted retinal locations. This is the first step in building a platform technology that will be used for a range of applications including visual psychophysics, temporal integration to enhance structural imaging, or monitoring of short term retinal changes of retinal cells in response to light stimulation.

This is a 2020 ARVO Annual Meeting abstract.