Contributed Session I: Towards clinically friendly optoretinography (ORG) using 100 kHz swept-source OCT without adaptive optics (AO)

Abstract

Optoretinography measures the stimulus-evoked response of the photoreceptors using light. Current systems use adaptive optics (AO) to obtain cellular-level resolution and fast volume acquisitions, to be able to monitor a single cone's response with sufficient sampling over time. The systems are complex to operate and therefore are not ideal in the clinical setting, where ease-of-use and high throughput are desirable. Here, we set out to explore if a less complex research-grade imaging system without AO could detect light-evoked changes in the retina when stimulus is applied. The imaging system uses 100 kHz swept source for OCT and tracking laser scanning ophthalmoscope is coupled into the sample arm for active eye-tracking. This provides a correction signal for the OCT to minimize spurious phase noise from eye motion. The stimulus is done with 555 nm LED (single flash and 10 Hz flicker) during OCT imaging. Obviously, the resolution is not the same without AO and signals are a collective response from tens of photoreceptors resulting in measurements of phase shift between scattering speckle fields rather than well-defined single reflections from within a photoreceptor. Improper eye tracking can also negatively affect phase-sensitive imaging needed to observe ORG signals. The ability to observe any stimulus-evoked responses using standard OCT would make optoretinography more accessible to study human vision as well as novel functional biomarkers of retinal diseases.