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

Abstract

Intrinsic optical signal (IOS) imaging of the retina, also termed as optoretinogram or optoretinography (ORG), promises a non-invasive method for the objective assessment of retinal function. By providing the unparalleled capability to differentiate individual retinal layers, functional optical coherence tomography (OCT) has been actively investigated for intrinsic signal ORG measurements. However, clinical deployment of functional OCT for quantitative ORG is still challenging due to the lack of a standardized imaging protocol and the complication of IOS sources and mechanisms. This article aims to summarize recent developments of functional OCT for ORG measurement, OCT intensity- and phase-based IOS processing. Technical challenges and perspectives of quantitative IOS analysis and ORG interpretations are discussed.

Two-photon excitation fluorescence in ophthalmology: safety and improved imaging for functional diagnostics

“…Such methods have been complemented with structural imaging, such as optical coherence tomography (OCT) (1,2), in which technology has advanced to allow for imaging of morphological changes, distinguishing healthy from sick/damaged eye OPEN ACCESS EDITED BY Bingyao Tan, Nanyang Technological University, Singapore components. However, there is a need for non-invasive functional imaging that will enable several advanced diagnostic approaches, including measurement of structural changes upon stimulus, for example with optoretinography (ORG) (3)(4)(5); direct assessment of biochemical changes, with two-photon (2Ph) imaging (6); and detection of human retinal fluorophores in situ in the interphase between the retina and the retinal pigment epithelium (RPE) layer to recognize imbalances in the visual cycle (6). 2Ph imaging is also helpful in examining the collagen arrangements in the human cornea and sclera and the non-collagen limbus ultrastructure of the trabecular meshwork (7).…”

Rotational Distortion and Compensation in Optical Coherence Tomography with Anisotropic Pixel Resolution

“…Image registration is also an imperative step for recently emerging optoretinography (ORG) [ 23 ]. ORG measures the stimulus-evoked intrinsic optical signal (IOS) changes, which reflect the functional status of retinal photoreceptors and inner neurons [ 23 ].…”

“…Image registration is also an imperative step for recently emerging optoretinography (ORG) [ 23 ]. ORG measures the stimulus-evoked intrinsic optical signal (IOS) changes, which reflect the functional status of retinal photoreceptors and inner neurons [ 23 ]. As ORG has a much higher spatial resolution than electroretinography (ERG), it has been actively studied in recent years [ 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 ].…”