Biology subjects

Vienola, K. V.

Publications and source records attributed to Vienola, K. V..

4 recordsLinked to original sources

bioRxiv2025

Insight into human photoreceptor function: modeling optoretinographic responses to diverse stimuli

Optoretinography is an emerging method for detecting and measuring functional responses from neurons in the living human retina. Its potential applications are significant and broad, spanning clinical assessment of retinal disease, investigation of fundamental scientific questions, and rapid evaluation of experimental therapeutics for blinding retinal diseases. Progress in all these domains hinges on the development of robust methods for quantifying observed responses in relation to visible stimuli. In this work, we describe a novel optoretinographic imaging platform-full-field swept-source optical coherence tomography with adaptive optics, measure cone responses in two healthy volunteers to a variety of stimulus patterns, and propose a simple model for predicting and quantifying responses to those stimuli. TeaserThe function of human retinal neurons is quantified by the light they reflect, opening a new frontier in visual health

physiology↗

bioRxiv2022

Velocity-based optoretinography for clinical applications

Optoretinography (ORG) is an emerging tool for testing neural function in the retina. Unlike existing methods, it is noninvasive, objective, and provides information about retinal structure and function at once. As such, it has great potential to transform ophthalmic care and clinical trials of novel therapeutics designed to restore or preserve visual function. Recent efforts have demonstrated the feasibility of the ORG using state-of-the-art optical coherence tomography systems. These methods measure the stimulus-evoked movement of subcellular features in the retina, using the phase of the reflected light to monitor their position. Here we present an alternative approach that monitors the velocity of these features instead. This conceptual shift has significant implications for the nascent field of optoretinography. By avoiding the need to track specific cells over time, it obviates costly and laborious aspects of the position-based approaches, such as adaptive optics, digital aberration correction, real-time tracking, and three-dimensional segmentation and registration. We used this novel velocity-based approach to measure the photoreceptor ORG responses in three healthy subjects. The resulting responses were reproducible and exhibited dependence on dose and retinal eccentricity. The position of the relevant structures was reconstructed through numerical integration of velocity.

neuroscience↗

bioRxiv2020

Improvements to multi-offset adaptive optics scanning laser ophthalmoscopy for in vivo imaging of individual retinal ganglion cell layer neurons in humans

Previous work has shown that multi-offset detection in adaptive optics scanning laser ophthalmoscopy (AOSLO) can be used to image retinal ganglion cells (RGCs) in monkeys and humans. However, though images of RGCs in anesthetized monkeys with high light levels produced high contrast images of RGCs, images from humans failed to reach the same contrast due to several drawbacks in the previous dual-wavelength multi-offset approach. Our aim here was to design and build a multi-offset detection pattern for humans at safe light levels that could reveal the retinal ganglion cell layer neurons with a contrast, robustness and acquisition time approaching results only previously obtained in monkeys. Here, we present a new imaging system using only one light source, compared to the previous dual-wavelength used on monkeys. Our single-wavelength solution allows for increased light power and eliminates problematic chromatic aberrations. Then, we demonstrate that a radial multi-offset detection pattern with an offset distance of 8-10 Airy Disk Diameter (ADD) is optimal to detect photons multiply scattered in all directions from RGCs thereby enhancing their contrast. This new setup and image processing pipeline led to improved imaging of retinal ganglion cells using multi-offset imaging in AOSLO.

bioengineering↗

bioRxiv2020

Kilohertz retinal FF-SS-OCT and flood imaging with hardware-based adaptive optics

A retinal imaging system was designed for full-field (FF) swept-source (SS) optical coherence tomography (OCT) with cellular resolution. The system incorporates a real-time adaptive optics (AO) subsystem and a very high speed CMOS sensor, and is capable of acquiring volumetric images of the retina at rates up to 1 kHz. While digital aberration correction (DAC) is an attractive potential alternative to AO, it has not yet been shown to provide resolution of cones in the fovea, where early detection of functional deficits is most critical. Here we demonstrate that FF-SS-OCT with hardware AO permits resolution of foveal cones, with volume rates adequate to measure light-evoked changes in photoreceptors. With the reference arm blocked, the system can operate as kilohertz AO flood illumination fundus camera with adjustable temporal coherence and is expected to allow measurement of light-evoked changes caused by common path interference in photoreceptor outer segments (OS). In this work, we describe the systems optical design, characterize its performance, and demonstrate its ability to produce images of the human photoreceptor mosaic.

bioengineering↗