Adaptive Optics Rolling Slit Ophthalmoscope: Combining cellular-resolution, high-speed and large field-of-view in a multimodal retinal imager

Abstract

Label-free optical imaging systems capable of monitoring dynamic biological processes over a large field-of-view (FOV) are essential for advancing our understanding of retinal and neurovascular health. However, existing imaging modalities often involve trade-offs between spatial resolution, contrast, FOV, and frame rate. In this study, we present the Adaptive Optics Rolling Slit Ophthalmoscope (AO-RSO), a novel imaging system that integrates the high-speed, wide-FOV capabilities of camera-based systems with the enhanced contrast and multimodal functionality of point-scanning techniques--without compromising resolution or speed. The AO-RSO utilizes line illumination synchronized with the rolling shutter of a high-speed sCMOS camera, enabling precise and dynamic spatial selection of detected photons: back-scattered photons for near-confocal bright-field imaging and forward-scattered photons for phase-contrast imaging of translucent retinal features. This system successfully visualizes diverse retinal structures, including cone and rod photoreceptors, nerve fiber bundles, red blood cells, vessel walls, and ganglion cells, across a wide retinal area (4.5{degrees}x 2.5{degrees}). With a large FOV and frame rates up to 200 Hz, the AO-RSO enables the quantification of blood flow, tracking of red blood cells within hundreds of capillaries, and evaluation of thousands of photoreceptors in the living human retina. This capability opens new opportunities for functional neuronal imaging, neurovascular coupling studies, and the early detection of retinal and neurodegenerative diseases.