Contributed Session I: Human cone response models for optoretinography with FF-SS-OCT and adaptive optics.

Abstract

Recent work has shown that human rod and cone outer segments (ROS and COS, respectively) deform in response to visual stimuli. In phase-based optoretinography (ORG) the phases of backscattered light from the inner/outer segment junction (IS/OS) and the COS/ROS tips (COST/ROST), is measured, which allows observation of stimulus-evoked, nanometer-scale changes in the OS length. In this work, we used a full-field swept-source OCT with AO that allowed up to kHz volume rates. ORG responses were recorded in two healthy volunteers, with photopigment bleaching levels in the range of 1-60 %, and modeled using an exponential sum. The proposed harmonic oscillator-based response model allowed us to describe the shape of the cone's ORG responses by amplitudes of deflection and relaxation times. Our preliminary results show that responses to complex stimuli were consistent with photopigment availability, which in the context of the consensus theory that adaptation in cones is mediated by photopigment suggests that the ORG may be a useful way to probe light adaptation in cones. The development of simple quantitative parameters describing the ORG response should benefit future clinical applications and help to track the progress of blinding diseases.