Volumetric data analysis enabled spatially resolved optoretinogram to measure the functional signals in the living retina

Abstract

Optoretinogram, a technique in which optical coherence tomography (OCT) is used to measure retinal functions in response to a visible light stimulus, can be a potentially useful tool to quantify retinal health alterations. Existing experimental studies on animals have focused on measuring the global retinal response by transversally averaging 3D data across the retina, which minimizes the spatial resolution of the signals, and limits the signal‐to‐noise ratio because only central B‐scans are collected and analyzed. These problems were addressed in this study by collecting volumetric data to probe functional signals and developing an improved 3D registration approach to align such series‐acquired OCT volumes. These data were then divided into small blocks and subject to a spatiotemporal analysis, whose results confirmed the spatial‐dependence of functional signals. By further averaging, the overall measurement accuracies for the position and the scattering signals were estimated to be approximately 30 nm and 1.1 %, respectively. With improved accuracy, this method revealed certain novel functional signals that have not been previously reported. In conclusion, this work provides a powerful tool to monitor retinal local and global functional changes in aging, diseased, or treated rodent eyes.

A comparison of optophysiological biomarkers of photoreceptor stress and phototoxicity in BALB/cJ, B6(Cg)-Tyrc-2J/J, and C57Bl/6J mouse strains

“…More recently, Zhang et al used LRPs to display results from OCT optophysiology studies used to identify back reflective signal changes caused by osmotic tension due to phototransduction within the visual cycle ( 38 ). Others have used LRP analysis to elucidate the differences between OCT images of albino and pigmented mice, primarily for differentiating the apical and basolateral aspects of the RPE relative to the photoreceptor outer segment apical tips and Bruch’s membrane, respectively ( 11 , 38 , 60 , 66 , 72 ). Visualization of a very thin hyporeflective band presumably in the vicinity of the sub-retinal space is induced by diurnal light/dark changes and presumably related to mitochondrial respiration, altering of pH and movement of water via the RPE ( 67 , 69 ).…”

A.I. Pipeline for Accurate Retinal Layer Segmentation Using OCT 3D Images

“…Standard AI-based classical techniques (for example Support Vector Machine, optical flow, and graph methods) are deployed for clinical applications as far as automated post-processing is a concern [21][22][23]. Deep Learning based models require thorough testing as far as the sensitivity of hyperparameters with respect to imaging data is required for optimal performance [24].…”

Functional Optical Coherence Tomography for Intrinsic Signal Optoretinography: Recent Developments and Deployment Challenges

“…A hybrid line-scan SLO and OCT system was also employed for confocal-OCT IOS imaging study of isolated retinas ( 47 ). Given the improved imaging speed, Fourier-domain OCT has dominated recent IOS imaging studies of both animal ( 33 , 35 , 37 , 39 , 42 , 44 , 48 – 52 ) and human ( 25 , 31 , 32 , 36 , 37 , 53 – 55 ) retinas.…”