Abstract

There have been several reports of in vivo probing of light-evoked responses of photoreceptors in humans and experimental animals. Specifically, the changes in outer segments lengths of dark-adapted rods and cones due to the visible optical stimuli that bleach fractions of their visual photopigment have been characterized in detail. We have previously developed an optical coherence tomography (OCT) intensity-based “optoretinograms” (ORG), the paradigm of using near-infrared OCT (NIR OCT) to measure bleaching-induced backscattering and/or elongation changes of photoreceptors in the eye of experimental animals in vivo. Recently we have extended this work to allow extraction of OCT phase-based “optoretinograms” in standard serial OCT B-scans in mice. The phase-based ORG in standard resolution OCT systems compared to adaptive optics enhanced cellular resolution AO-OCT is more demanding to implement and has not been explored extensively. This manuscript describes implementation of a phase analysis framework, previously developed for mice retinal ORG extraction, to clinical retinal images acquired with a standard resolution and raster scanning OCT system offering much lower phase stability than line-field or full-field OCT detection schemes. Our initial results showcase the successful extraction of phase-based ORG signal from the B-scans acquired at ~400 Hz rate. Our calculation of phase-based ORG signals relies on Knox-Thompson paths and modified signal recovery by adding decorrelation weights. This phase-sensitive ORG signal analysis using clinical-grade raster scanning OCT systems should provide a direction for clinically friendly ORG probing.

© 2022 The Author(s)