51
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Lee KE, Heitkotter H, Carroll J. Challenges Associated With Ellipsoid Zone Intensity Measurements Using Optical Coherence Tomography. Transl Vis Sci Technol 2021; 10:27. [PMID: 34665233 PMCID: PMC8543396 DOI: 10.1167/tvst.10.12.27] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 09/16/2021] [Indexed: 12/11/2022] Open
Abstract
Translational Relevance Qualitative evaluation of the ellipsoid zone band on optical coherence tomography is a valuable clinical tool for assessing photoreceptor structure, though more quantitative metrics are emerging. Awareness of the challenges involved in interpreting quantitative metrics is important for their clinical translation.
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Affiliation(s)
- Karen E. Lee
- Medical College of Wisconsin, Milwaukee, WI, USA
| | - Heather Heitkotter
- Cell Biology, Neurobiology & Anatomy, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Joseph Carroll
- Cell Biology, Neurobiology & Anatomy, Medical College of Wisconsin, Milwaukee, WI, USA
- Ophthalmology & Visual Sciences, Medical College of Wisconsin, Milwaukee, WI, USA
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52
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Brais-Brunet S, Heckel É, Kanniyappan U, Chemtob S, Boudoux C, Joyal JS, Dehaes M. Morphometric and Microstructural Changes During Murine Retinal Development Characterized Using In Vivo Optical Coherence Tomography. Invest Ophthalmol Vis Sci 2021; 62:20. [PMID: 34698774 PMCID: PMC8556565 DOI: 10.1167/iovs.62.13.20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Purpose The purpose of this study was to develop an in vivo optical coherence tomography (OCT) system capable of imaging the developing mouse retina and its associated morphometric and microstructural changes. Methods Thirty-four wild-type mice (129S1/SvlmJ) were anesthetized and imaged between postnatal (P) day 7 and P21. OCT instrumentation was developed to optimize signal intensity and image quality. Semi-automatic segmentation tools were developed to quantify the retinal thickness of the nerve fiber layer (NFL), inner plexiform layer (IPL), inner nuclear layer (INL), and the outer retinal layers (ORL), in addition to the total retina. The retinal maturation was characterized by comparing layer thicknesses between consecutive time points. Results From P7 to P10, the IPL increased significantly, consistent with retinal synaptogenesis. From P10 to P12, the IPL and ORL also increased, which is coherent with synaptic connectivity and photoreceptor maturation. In contrast, during these periods, the INL decreased significantly, consistent with cellular densification and selective apoptotic “pruning” of the tissue during nuclear migration. Thereafter from P12 to P21, the INL continued to thin (significantly from P17 to P21) whereas the other layers remained unchanged. No time-dependent changes were observed in the NFL. Overall, changes in the total retina were attributed to those in the IPL, INL, and ORL. Regions of the retina adjacent to the optic nerve head were thinner than distal regions during maturation. Conclusions Changes in retinal layer thickness are consistent with retinal developmental mechanisms. Accordingly, this report opens new horizons in using our system in the mouse to characterize longitudinally developmental digressions in models of human diseases.
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Affiliation(s)
- Simon Brais-Brunet
- Institute of Biomedical Engineering, University of Montréal, Montréal, Canada.,Research Center, CHU Sainte-Justine, Montréal, Canada
| | - Émilie Heckel
- Research Center, CHU Sainte-Justine, Montréal, Canada.,Department of Pharmacology, University of Montréal, Montréal, Canada
| | - Udayakumar Kanniyappan
- Institute of Biomedical Engineering, University of Montréal, Montréal, Canada.,Research Center, CHU Sainte-Justine, Montréal, Canada
| | - Sylvain Chemtob
- Research Center, CHU Sainte-Justine, Montréal, Canada.,Department of Pharmacology, University of Montréal, Montréal, Canada.,Department of Pediatrics, University of Montréal, Montréal, Canada.,Department of Ophthalmology, University of Montréal, Montréal, Canada
| | - Caroline Boudoux
- Research Center, CHU Sainte-Justine, Montréal, Canada.,Department of Engineering Physics, Polytechnique Montréal, Montréal, Canada
| | - Jean-Sébastien Joyal
- Research Center, CHU Sainte-Justine, Montréal, Canada.,Department of Pharmacology, University of Montréal, Montréal, Canada.,Department of Pediatrics, University of Montréal, Montréal, Canada.,Department of Ophthalmology, University of Montréal, Montréal, Canada
| | - Mathieu Dehaes
- Institute of Biomedical Engineering, University of Montréal, Montréal, Canada.,Research Center, CHU Sainte-Justine, Montréal, Canada.,Department of Radiology, Radio-oncology and Nuclear Medicine, University of Montréal, Montréal, Canada
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53
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Leitgeb R, Placzek F, Rank E, Krainz L, Haindl R, Li Q, Liu M, Andreana M, Unterhuber A, Schmoll T, Drexler W. Enhanced medical diagnosis for dOCTors: a perspective of optical coherence tomography. JOURNAL OF BIOMEDICAL OPTICS 2021; 26:JBO-210150-PER. [PMID: 34672145 PMCID: PMC8528212 DOI: 10.1117/1.jbo.26.10.100601] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 09/23/2021] [Indexed: 05/17/2023]
Abstract
SIGNIFICANCE After three decades, more than 75,000 publications, tens of companies being involved in its commercialization, and a global market perspective of about USD 1.5 billion in 2023, optical coherence tomography (OCT) has become one of the fastest successfully translated imaging techniques with substantial clinical and economic impacts and acceptance. AIM Our perspective focuses on disruptive forward-looking innovations and key technologies to further boost OCT performance and therefore enable significantly enhanced medical diagnosis. APPROACH A comprehensive review of state-of-the-art accomplishments in OCT has been performed. RESULTS The most disruptive future OCT innovations include imaging resolution and speed (single-beam raster scanning versus parallelization) improvement, new implementations for dual modality or even multimodality systems, and using endogenous or exogenous contrast in these hybrid OCT systems targeting molecular and metabolic imaging. Aside from OCT angiography, no other functional or contrast enhancing OCT extension has accomplished comparable clinical and commercial impacts. Some more recently developed extensions, e.g., optical coherence elastography, dynamic contrast OCT, optoretinography, and artificial intelligence enhanced OCT are also considered with high potential for the future. In addition, OCT miniaturization for portable, compact, handheld, and/or cost-effective capsule-based OCT applications, home-OCT, and self-OCT systems based on micro-optic assemblies or photonic integrated circuits will revolutionize new applications and availability in the near future. Finally, clinical translation of OCT including medical device regulatory challenges will continue to be absolutely essential. CONCLUSIONS With its exquisite non-invasive, micrometer resolution depth sectioning capability, OCT has especially revolutionized ophthalmic diagnosis and hence is the fastest adopted imaging technology in the history of ophthalmology. Nonetheless, OCT has not been completely exploited and has substantial growth potential-in academics as well as in industry. This applies not only to the ophthalmic application field, but also especially to the original motivation of OCT to enable optical biopsy, i.e., the in situ imaging of tissue microstructure with a resolution approaching that of histology but without the need for tissue excision.
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Affiliation(s)
- Rainer Leitgeb
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
- Medical University of Vienna, Christian Doppler Laboratory OPTRAMED, Vienna, Austria
| | - Fabian Placzek
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
| | - Elisabet Rank
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
| | - Lisa Krainz
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
| | - Richard Haindl
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
| | - Qian Li
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
| | - Mengyang Liu
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
| | - Marco Andreana
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
| | - Angelika Unterhuber
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
| | - Tilman Schmoll
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
- Carl Zeiss Meditec, Inc., Dublin, California, United States
| | - Wolfgang Drexler
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
- Address all correspondence to Wolfgang Drexler,
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54
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Jonnal RS. Toward a clinical optoretinogram: a review of noninvasive, optical tests of retinal neural function. ANNALS OF TRANSLATIONAL MEDICINE 2021; 9:1270. [PMID: 34532407 PMCID: PMC8421939 DOI: 10.21037/atm-20-6440] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 07/12/2021] [Indexed: 11/17/2022]
Abstract
The past few years have witnessed rapid development of the optoretinogram—a noninvasive, optical measurement of neural function in the retina, and especially the photoreceptors (Ph). While its recent development has been rapid, it represents the culmination of hundreds of experiments spanning decades. Early work showed measurable and reproducible changes in the optical properties of retinal explants and suspensions of Ph, and uncovered some of the biophysical and biochemical mechanisms underlying them. That work thus provided critical motivation for more recent work based on clinical imaging platforms, whose eventual goal is the improvement of ophthalmic care and streamlining the discovery of novel therapeutics. The first part of this review consists of a selective summary of the early work, and identifies four kinds of stimulus-evoked optical signals that have emerged from it: changes in light scattered from the membranous discs of the Ph’s outer segment (OS), changes in light scattered by the front and back boundaries of the OS, rearrangement of scattering material in and near the OS, and changes in the OS length. In the past decade, all four of these signals have continued to be investigated using imaging systems already used in the clinic or intended for clinical and translational use. The second part of this review discusses these imaging modalities, their potential to detect and quantify the signals of interest, and other factors influencing their translational promise. Particular attention is paid to phase-sensitive optical coherence tomography (OCT) with adaptive optics (AO), a method in which both the amplitude and the phase of light reflected from individual Ph is monitored as visible stimuli are delivered to them. The record of the light’s phase is decoded to reveal a reproducible pattern of deformation in the OS, while the amplitude reveals changes in scattering and structural rearrangements. The method has been demonstrated in a few labs and has been used to measure responses from both rods and cones. With the ability to detect responses to stimuli isomerizing less than 0.01% of photopigment, this technique may prove to be a quick, noninvasive, and objective way to measure subtle disease-related dysfunction at the cellular level, and thus to provide an entirely new and complementary biomarker for retinal disease and recovery.
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Affiliation(s)
- Ravi S Jonnal
- Department of Ophthalmology and Vision Science, University of California, Davis, CA, USA
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55
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Pandiyan VP, Jiang X, Kuchenbecker JA, Sabesan R. Reflective mirror-based line-scan adaptive optics OCT for imaging retinal structure and function. BIOMEDICAL OPTICS EXPRESS 2021; 12:5865-5880. [PMID: 34692221 PMCID: PMC8515964 DOI: 10.1364/boe.436337] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 08/16/2021] [Accepted: 08/20/2021] [Indexed: 05/06/2023]
Abstract
Line-scan OCT incorporated with adaptive optics (AO) offers high resolution, speed, and sensitivity for imaging retinal structure and function in vivo. Here, we introduce its implementation with reflective mirror-based afocal telescopes, optimized for imaging light-induced retinal activity (optoretinography) and weak retinal reflections at the cellular scale. A non-planar optical design was followed based on previous recommendations with key differences specific to a line-scan geometry. The three beam paths fundamental to an OCT system -illumination/sample, detection, and reference- were modeled in Zemax optical design software to yield theoretically diffraction-limited performance over a 2.2 deg. field-of-view and 1.5 D vergence range at the eye's pupil. The performance for imaging retinal structure was exemplified by cellular-scale visualization of retinal ganglion cells, macrophages, foveal cones, and rods in human observers. The performance for functional imaging was exemplified by resolving the light-evoked optical changes in foveal cone photoreceptors where the spatial resolution was sufficient for cone spectral classification at an eccentricity 0.3 deg. from the foveal center. This enabled the first in vivo demonstration of reduced S-cone (short-wavelength cone) density in the human foveola, thus far observed only in ex vivo histological preparations. Together, the feasibility for high resolution imaging of retinal structure and function demonstrated here holds significant potential for basic science and translational applications.
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Affiliation(s)
- Vimal Prabhu Pandiyan
- Department of Ophthalmology, University of Washington School of Medicine, Seattle, WA 98109, USA
- Co-first authors with equal contribution
| | - Xiaoyun Jiang
- Department of Ophthalmology, University of Washington School of Medicine, Seattle, WA 98109, USA
- Co-first authors with equal contribution
| | - James A Kuchenbecker
- Department of Ophthalmology, University of Washington School of Medicine, Seattle, WA 98109, USA
| | - Ramkumar Sabesan
- Department of Ophthalmology, University of Washington School of Medicine, Seattle, WA 98109, USA
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56
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Gaffney M, Cooper RF, Cava JA, Follett HM, Salmon AE, Freling S, Yu CT, Merriman DK, Carroll J. Cone photoreceptor reflectance variation in the northern tree shrew and thirteen-lined ground squirrel. Exp Biol Med (Maywood) 2021; 246:2192-2201. [PMID: 34308656 DOI: 10.1177/15353702211029582] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
In vivo images of human cone photoreceptors have been shown to vary in their reflectance both spatially and temporally. While it is generally accepted that the unique anatomy and physiology of the photoreceptors themselves drives this behavior, the exact mechanisms have not been fully elucidated as most studies on these phenomena have been limited to the human retina. Unlike humans, animal models offer the ability to experimentally manipulate the retina and perform direct in vivo and ex vivo comparisons. The thirteen-lined ground squirrel and northern tree shrew are two emerging animal models being used in vision research. Both models feature cone-dominant retinas, overcoming a key limitation of traditional rodent models. Additionally, each possesses unique but well-documented anatomical differences in cone structure compared to human cones, which can be leveraged to further constrain theoretical models of light propagation within photoreceptors. Here we sought to characterize the spatial and temporal reflectance behavior of cones in these species. Adaptive optics scanning light ophthalmoscopy (AOSLO) was used to non-invasively image the photoreceptors of both species at 5 to 10 min intervals over the span of 18 to 25 min. The reflectance of individual cone photoreceptors was measured over time, and images at individual time points were used to assess the variability of cone reflectance across the cone mosaic. Variability in spatial and temporal photoreceptor reflectance was observed in both species, with similar behavior to that seen in human AOSLO images. Despite the unique cone structure in these animals, these data suggest a common origin of photoreceptor reflectance behavior across species. Such data may help constrain models of the cellular origins of photoreceptor reflectance signals. These animal models provide an experimental platform to further explore the morphological origins of light capture and propagation.
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Affiliation(s)
- Mina Gaffney
- Department of Ophthalmology & Visual Sciences, 5506Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Robert F Cooper
- Department of Ophthalmology & Visual Sciences, 5506Medical College of Wisconsin, Milwaukee, WI 53226, USA.,Department of Biomedical Engineering, 5505Marquette University, Milwaukee, WI 53233, USA
| | - Jenna A Cava
- Department of Ophthalmology & Visual Sciences, 5506Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Hannah M Follett
- Department of Ophthalmology & Visual Sciences, 5506Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Alexander E Salmon
- Department of Cell Biology, Neurobiology, & Anatomy, 5506Medical College of Wisconsin, Milwaukee, WI 53226, USA.,Translational Imaging Innovations, Inc., Hickory, NC 28601, USA
| | - Susan Freling
- 164174Max Planck Florida Institute for Neuroscience, Jupiter, FL 33458, USA
| | - Ching T Yu
- Department of Cell Biology, Neurobiology, & Anatomy, 5506Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Dana K Merriman
- Department of Biology, 14752University of Wisconsin Oshkosh, Oshkosh, WI 54901, USA
| | - Joseph Carroll
- Department of Ophthalmology & Visual Sciences, 5506Medical College of Wisconsin, Milwaukee, WI 53226, USA.,Department of Biomedical Engineering, 5505Marquette University, Milwaukee, WI 53233, USA.,Department of Cell Biology, Neurobiology, & Anatomy, 5506Medical College of Wisconsin, Milwaukee, WI 53226, USA
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57
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Zhang F, Kurokawa K, Bernucci MT, Jung HW, Lassoued A, Crowell JA, Neitz J, Neitz M, Miller DT. Revealing How Color Vision Phenotype and Genotype Manifest in Individual Cone Cells. Invest Ophthalmol Vis Sci 2021; 62:8. [PMID: 33544131 PMCID: PMC7873503 DOI: 10.1167/iovs.62.2.8] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Purpose Psychophysical and genetic testing provide substantial information about color vision phenotype and genotype. However, neither reveals how color vision phenotypes and genotypes manifest themselves in individual cones, where color vision and its anomalies are thought to originate. Here, we use adaptive-optics phase-sensitive optical coherence tomography (AO-PSOCT) to investigate these relationships. Methods We used AO-PSOCT to measure cone function—optical response to light stimulation—in each of 16 human subjects with different phenotypes and genotypes of color vision (five color-normal, three deuteranopic, two protanopic, and six deuteranomalous trichromatic subjects). We classified three spectral types of cones (S, M, and L), and we measured cone structure—namely cone density, cone mosaic arrangement, and spatial arrangement of cone types. Results For the different phenotypes, our cone function results show that (1) color normals possess S, M, and L cones; (2) deuteranopes are missing M cones but are normal otherwise; (3) protanopes are missing L cones but are normal otherwise; and (4) deuteranomalous trichromats are missing M cones but contain evidence of at least two subtypes of L cones. Cone function was consistent with the subjects’ genotype in which only the first two M and L genes in the gene array are expressed and was correlated with the estimated spectral separation between photopigments, including in the deuteranomalous trichromats. The L/M cone ratio was highly variable in the color normals. No association was found between cone density and the genotypes and phenotypes investigated, and the cone mosaic arrangement was altered in the dichromats. Conclusions AO-PSOCT is a novel method for assessing color vision phenotype and genotype in single cone cells.
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Affiliation(s)
- Furu Zhang
- School of Optometry, Indiana University, Bloomington, Indiana, United States.,Center for Devices and Radiological Health, Food and Drug Administration, Silver Spring, Maryland, United States
| | - Kazuhiro Kurokawa
- School of Optometry, Indiana University, Bloomington, Indiana, United States
| | - Marcel T Bernucci
- School of Optometry, Indiana University, Bloomington, Indiana, United States
| | - Hae Won Jung
- School of Optometry, Indiana University, Bloomington, Indiana, United States
| | - Ayoub Lassoued
- School of Optometry, Indiana University, Bloomington, Indiana, United States
| | - James A Crowell
- School of Optometry, Indiana University, Bloomington, Indiana, United States
| | - Jay Neitz
- Department of Ophthalmology, University of Washington, Seattle, Washington, United States
| | - Maureen Neitz
- Department of Ophthalmology, University of Washington, Seattle, Washington, United States
| | - Donald T Miller
- School of Optometry, Indiana University, Bloomington, Indiana, United States
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58
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Salmon AE, Chen RCH, Atry F, Gaffney M, Merriman DK, Gil DA, Skala MC, Collery R, Allen KP, Buckland E, Pashaie R, Carroll J. Optical Coherence Tomography Angiography in the Thirteen-Lined Ground Squirrel. Transl Vis Sci Technol 2021; 10:5. [PMID: 34232271 PMCID: PMC8267221 DOI: 10.1167/tvst.10.8.5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose To assess the performance of two spectral-domain optical coherence tomography-angiography systems in a natural model of hypoperfusion: the hibernating thirteen-lined ground squirrel (13-LGS). Methods Using a high-speed (130 kHz) OCT-A system (HS-OCT-A) and a commercial OCT (36 kHz; Bioptigen Envisu; BE-OCT-A), we imaged the 13-LGS retina throughout its hibernation cycle. Custom software was used to extract the superior, middle, and deep capillary plexus (SCP, MCP, and DCP, respectively). The retinal vasculature was also imaged with adaptive optics scanning light ophthalmoscopy (AOSLO) during torpor to visualize individual blood cells. Finally, correlative histology with immunolabeled or DiI-stained vasculature was performed. Results During euthermia, vessel density was similar between devices for the SCP and MCP (P = 0.88, 0.72, respectively), with a small difference in the DCP (−1.63 ± 1.54%, P = 0.036). Apparent capillary dropout was observed during torpor, but recovered after forced arousal, and this effect was exaggerated in high-speed OCT-A imaging. Based on cell flux measurements with AOSLO, increasing OCT-A scan duration by ∼1000× would avoid the apparent capillary dropout artifact. High correspondence between OCT-A (during euthermia) and histology enabled lateral scale calibration. Conclusions While the HS-OCT-A system provides a more efficient workflow, the shorter interscan interval may render it more susceptible to the apparent capillary dropout artifact. Disambiguation between capillary dropout and transient ischemia can have important implications in the management of retinal disease and warrants additional diagnostics. Translational Relevance The 13-LGS provides a natural model of hypoperfusion that may prove valuable in modeling the utility of OCT-A in human pathologies associated with altered blood flow.
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Affiliation(s)
- Alexander E Salmon
- Cell Biology, Neurobiology, & Anatomy, Medical College of Wisconsin, Milwaukee, WI, USA.,Translational Imaging Innovations, Hickory, NC, USA
| | - Rex Chin-Hao Chen
- Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, USA
| | - Farid Atry
- Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, USA
| | - Mina Gaffney
- Ophthalmology & Visual Sciences, Medical College of Wisconsin, Milwaukee, WI, USA
| | | | - Daniel A Gil
- Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, USA.,Morgridge Institute for Research, Madison, WI, USA
| | - Melissa C Skala
- Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, USA.,Morgridge Institute for Research, Madison, WI, USA
| | - Ross Collery
- Cell Biology, Neurobiology, & Anatomy, Medical College of Wisconsin, Milwaukee, WI, USA.,Ophthalmology & Visual Sciences, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Kenneth P Allen
- Microbiology & Immunology, Medical College of Wisconsin, Milwaukee, WI, USA
| | | | - Ramin Pashaie
- Computer & Electrical Engineering, Florida Atlantic University, Boca Raton, FL, USA
| | - Joseph Carroll
- Cell Biology, Neurobiology, & Anatomy, Medical College of Wisconsin, Milwaukee, WI, USA.,Ophthalmology & Visual Sciences, Medical College of Wisconsin, Milwaukee, WI, USA.,Biomedical Engineering, Marquette University, Milwaukee WI, USA
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Yao X, Son T, Kim TH, Le D. Interpretation of anatomic correlates of outer retinal bands in optical coherence tomography. Exp Biol Med (Maywood) 2021; 246:2140-2150. [PMID: 34111984 DOI: 10.1177/15353702211022674] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
By providing the sectioning capability to differentiate individual retinal layers, optical coherence tomography (OCT) is revolutionizing eye disease diagnosis and treatment evaluation. A better understanding of the hyper- and hypo-reflective bands in retinal OCT is essential for accurate interpretation of clinical outcomes. In this article, we summarize the interpretations of clinical OCT and adaptive optics (AO) OCT (AO-OCT) of the outer retina in the human eye, and briefly review OCT investigation of the outer retina in animal models. Quantitative analysis of outer retinal OCT bands is compared to established parameters of retinal histology. The literature review and comparative analysis support that both inner/outer segment (IS/OS) junction and IS ellipsoid zone nonexclusively contribute to the second band; and OS, OS tips, and retinal pigment epithelium apical processes contribute to the third band in conventional OCT. In contrast, AO-OCT might predominantly detect the IS/OS junction and OS tip signals at the second and third bands due to its improved sectioning capability and possible AO effect on the sensitivities for recording ballistic and diffusive photons from different regions of the outer retina.
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Affiliation(s)
- Xincheng Yao
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA.,Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Taeyoon Son
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Tae-Hoon Kim
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - David Le
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
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Berkowitz BA, Qian H. OCT imaging of rod mitochondrial respiration in vivo. Exp Biol Med (Maywood) 2021; 246:2151-2158. [PMID: 34024141 DOI: 10.1177/15353702211013799] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
There remains a need for high spatial resolution imaging indices of mitochondrial respiration in the outer retina that probe normal physiology and measure pathogenic and reversible conditions underlying loss of vision. Mitochondria are involved in a critical, but somewhat underappreciated, support system that maintains the health of the outer retina involving stimulus-evoked changes in subretinal space hydration. The subretinal space hydration light-dark response is important because it controls the distribution of vision-critical interphotoreceptor matrix components, including anti-oxidants, pro-survival factors, ions, and metabolites. The underlying signaling pathway controlling subretinal space water management has been worked out over the past 30 years and involves cGMP/mitochondria respiration/pH/RPE water efflux. This signaling pathway has also been shown to be modified by disease-generating conditions, such as hypoxia or oxidative stress. Here, we review recent advances in MRI and commercially available OCT technologies that can measure stimulus-evoked changes in subretinal space water content based on changes in the external limiting membrane-retinal pigment epithelium region. Each step within the above signaling pathway can also be interrogated with FDA-approved pharmaceuticals. A highlight of these studies is the demonstration of first-in-kind in vivo imaging of mitochondria respiration of any cell in the body. Future examinations of subretinal space hydration are expected to be useful for diagnosing threats to sight in aging and disease, and improving the success rate when translating treatments from bench-to-bedside.
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Affiliation(s)
- Bruce A Berkowitz
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University School of Medicine, Detroit, MI 48201, USA
| | - Haohua Qian
- Visual Function Core, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
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61
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Gao S, Li Y, Bissig D, Cohen ED, Podolsky RH, Childers KL, Vernon G, Chen S, Berkowitz BA, Qian H. Functional regulation of an outer retina hyporeflective band on optical coherence tomography images. Sci Rep 2021; 11:10260. [PMID: 33986362 PMCID: PMC8119672 DOI: 10.1038/s41598-021-89599-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 04/27/2021] [Indexed: 12/30/2022] Open
Abstract
Human and animal retinal optical coherence tomography (OCT) images show a hyporeflective band (HB) between the photoreceptor tip and retinal pigment epithelium layers whose mechanisms are unclear. In mice, HB magnitude and the external limiting membrane-retinal pigment epithelium (ELM-RPE) thickness appear to be dependent on light exposure, which is known to alter photoreceptor mitochondria respiration. Here, we test the hypothesis that these two OCT biomarkers are linked to metabolic activity of the retina. Acetazolamide, which acidifies the subretinal space, had no significant impact on HB magnitude but produced ELM-RPE thinning. Mitochondrial stimulation with 2,4-dinitrophenol reduced both HB magnitude and ELM-RPE thickness in parallel, and also reduced F-actin expression in the same retinal region, but without altering ERG responses. For mice strains with relatively lower (C57BL/6J) or higher (129S6/ev) rod mitochondrial efficacy, light-induced changes in HB magnitude and ELM-RPE thickness were correlated. Humans, analyzed from published data captured with a different protocol, showed a similar light–dark change pattern in HB magnitude as in the mice. Our results indicate that mitochondrial respiration underlies changes in HB magnitude upstream of the pH-sensitive ELM-RPE thickness response. These two distinct OCT biomarkers could be useful indices for non-invasively evaluating photoreceptor mitochondrial metabolic activity.
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Affiliation(s)
- Shasha Gao
- Department of Ophthalmology, the First Affiliated Hospital, Zhengzhou University, Zhengzhou, China.,Visual Function Core, National Eye Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Yichao Li
- Visual Function Core, National Eye Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - David Bissig
- Department of Neurology, University of California Davis, Sacramento, CA, USA
| | - Ethan D Cohen
- Division of Biomedical Physics, Office of Science and Engineering Labs, Center for Devices and Radiological Health, Food and Drug Administration, Silver Spring, MD, USA
| | - Robert H Podolsky
- Beaumont Research Institute, Beaumont Health, Royal Oak, MI, 48073, USA
| | | | - Gregory Vernon
- Visual Function Core, National Eye Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Sonia Chen
- Visual Function Core, National Eye Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Bruce A Berkowitz
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University School of Medicine, Detroit, MI, USA
| | - Haohua Qian
- Visual Function Core, National Eye Institute, National Institutes of Health, Bethesda, MD, 20892, USA.
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62
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Ma G, Son T, Kim TH, Yao X. In vivo optoretinography of phototransduction activation and energy metabolism in retinal photoreceptors. JOURNAL OF BIOPHOTONICS 2021; 14:e202000462. [PMID: 33547871 PMCID: PMC8240094 DOI: 10.1002/jbio.202000462] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 01/09/2021] [Accepted: 02/02/2021] [Indexed: 05/05/2023]
Abstract
The objective of this study is to verify the anatomic correlate of the second (2nd) outer retina band in optical coherence tomography (OCT), and to demonstrate the potential of using intrinsic optical signal (IOS) imaging for concurrent optoretinography (ORG) of phototransduction activation and energy metabolism in stimulus activated retinal photoreceptors. A custom-designed OCT was employed for depth-resolved IOS imaging in mouse retina activated by a visible light flicker stimulation. The spatiotemporal properties of the IOS changes at the photoreceptor outer segment (OS) and inner segment (IS) were quantitatively evaluated. Rapid IOS change was observed at the OS almost right away, and the IOS at the IS was relatively slow. Comparative analysis indicates that the OS-IOS reflects transient OS deformation caused by the phototransduction activation, and IS-IOS might reflect the energy metabolism caused by mitochondria activation in retinal photoreceptors. The consistency of the distribution of the IS-IOS and the 2nd OCT band supports the IS ellipsoid (ISe), which has abundant mitochondria, as the signal source of the 2nd OCT band of the outer retina.
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Affiliation(s)
- Guangying Ma
- Department of Bioengineering, University of Illinois at Chicago, Chicago, Illinois
| | - Taeyoon Son
- Department of Bioengineering, University of Illinois at Chicago, Chicago, Illinois
| | - Tae-Hoon Kim
- Department of Bioengineering, University of Illinois at Chicago, Chicago, Illinois
| | - Xincheng Yao
- Department of Bioengineering, University of Illinois at Chicago, Chicago, Illinois
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, Illinois
- Correspondence: Xincheng Yao, Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA.
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63
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Ma G, Son T, Kim TH, Yao X. Functional optoretinography: concurrent OCT monitoring of intrinsic signal amplitude and phase dynamics in human photoreceptors. BIOMEDICAL OPTICS EXPRESS 2021; 12:2661-2669. [PMID: 34123495 PMCID: PMC8176815 DOI: 10.1364/boe.423733] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 03/31/2021] [Accepted: 04/02/2021] [Indexed: 05/12/2023]
Abstract
Intrinsic optical signal (IOS) imaging promises a noninvasive method for objective assessment of retinal function. This study demonstrates concurrent optical coherence tomography (OCT) of amplitude-IOS and phase-IOS changes in human photoreceptors. A new procedure for differential-phase-mapping (DPM) is validated to enable depth-resolved phase-IOS imaging. Dynamic OCT revealed rapid amplitude-IOS and phase-IOS changes, which occur almost right away after the stimulus onset. These IOS changes were predominantly observed within the photoreceptor outer segment (OS), particularly two boundaries connecting to the inner segment and retinal pigment epithelium. The comparative analysis supports that both amplitude-IOS and phase-IOS attribute to transient OS morphological change associated with phototransduction activation in retinal photoreceptors. A simulation modeling is proposed to discuss the relationship between the photoreceptor OS length and phase-IOS changes.
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Affiliation(s)
- Guangying Ma
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Taeyoon Son
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Tae-Hoon Kim
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Xincheng Yao
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL 60612, USA
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64
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Tang J, Cheng X, Kilic K, Devor A, Lee J, Boas DA. Imaging localized fast optical signals of neural activation with optical coherence tomography in awake mice. OPTICS LETTERS 2021; 46:1744-1747. [PMID: 33793533 PMCID: PMC8086197 DOI: 10.1364/ol.411897] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 03/10/2021] [Indexed: 05/05/2023]
Abstract
We report optical coherence tomography (OCT) imaging of localized fast optical signals (FOSs) arising from whisker stimulation in awake mice. The activated voxels were identified by fitting the OCT intensity signal time course with a response function over a time scale of a few hundred milliseconds after the whisker stimulation. The significantly activated voxels were shown to be localized to the expected brain region for whisker stimulation. The ability to detect functional stimulus-evoked, depth-resolved FOS with intrinsic contrast from the cortex provides a new tool for neural activity studies.
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Affiliation(s)
- Jianbo Tang
- Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
- Neurophotonics Center, Department of Biomedical Engineering, Boston University, Boston, Massachusetts 02215, USA
| | - Xiaojun Cheng
- Neurophotonics Center, Department of Biomedical Engineering, Boston University, Boston, Massachusetts 02215, USA
| | - Kivilcim Kilic
- Neurophotonics Center, Department of Biomedical Engineering, Boston University, Boston, Massachusetts 02215, USA
| | - Anna Devor
- Neurophotonics Center, Department of Biomedical Engineering, Boston University, Boston, Massachusetts 02215, USA
| | - Jonghwan Lee
- School of Engineering, Carney Institute for Brain Science, Brown University, Providence, Rhode Island 02912, USA
| | - David A. Boas
- Neurophotonics Center, Department of Biomedical Engineering, Boston University, Boston, Massachusetts 02215, USA
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65
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Li Z, Pandiyan VP, Maloney-Bertelli A, Jiang X, Li X, Sabesan R. Correcting intra-volume distortion for AO-OCT using 3D correlation based registration. OPTICS EXPRESS 2020; 28:38390-38409. [PMID: 33379652 PMCID: PMC7771894 DOI: 10.1364/oe.410374] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 11/15/2020] [Accepted: 11/19/2020] [Indexed: 05/18/2023]
Abstract
Adaptive optics (AO) based ophthalmic imagers, such as scanning laser ophthalmoscopes (SLO) and optical coherence tomography (OCT), are used to evaluate the structure and function of the retina with high contrast and resolution. Fixational eye movements during a raster-scanned image acquisition lead to intra-frame and intra-volume distortion, resulting in an inaccurate reproduction of the underlying retinal structure. For three-dimensional (3D) AO-OCT, segmentation-based and 3D correlation based registration methods have been applied to correct eye motion and achieve a high signal-to-noise ratio registered volume. This involves first selecting a reference volume, either manually or automatically, and registering the image/volume stream against the reference using correlation methods. However, even within the chosen reference volume, involuntary eye motion persists and affects the accuracy with which the 3D retinal structure is finally rendered. In this article, we introduced reference volume distortion correction for AO-OCT using 3D correlation based registration and demonstrate a significant improvement in registration performance via a few metrics. Conceptually, the general paradigm follows that developed previously for intra-frame distortion correction for 2D raster-scanned images, as in an AOSLO, but extended here across all three spatial dimensions via 3D correlation analyses. We performed a frequency analysis of eye motion traces before and after intra-volume correction and revealed how periodic artifacts in eye motion estimates are effectively reduced upon correction. Further, we quantified how the intra-volume distortions and periodic artifacts in the eye motion traces, in general, decrease with increasing AO-OCT acquisition speed. Overall, 3D correlation based registration with intra-volume correction significantly improved the visualization of retinal structure and estimation of fixational eye movements.
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Affiliation(s)
- Zhenghan Li
- Key Laboratory on Adaptive Optics, Chinese Academy of Sciences, Chengdu, Sichuan 610209, China
- Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu, Sichuan 610209, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- Department of Ophthalmology, University of Washington, Seattle, Washington 98109, USA
- These authors contributed equally to this work
| | - Vimal Prabhu Pandiyan
- Department of Ophthalmology, University of Washington, Seattle, Washington 98109, USA
- These authors contributed equally to this work
| | | | - Xiaoyun Jiang
- Department of Ophthalmology, University of Washington, Seattle, Washington 98109, USA
| | - Xinyang Li
- Key Laboratory on Adaptive Optics, Chinese Academy of Sciences, Chengdu, Sichuan 610209, China
- Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu, Sichuan 610209, China
| | - Ramkumar Sabesan
- Department of Ophthalmology, University of Washington, Seattle, Washington 98109, USA
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66
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Wynne N, Carroll J, Duncan JL. Promises and pitfalls of evaluating photoreceptor-based retinal disease with adaptive optics scanning light ophthalmoscopy (AOSLO). Prog Retin Eye Res 2020; 83:100920. [PMID: 33161127 DOI: 10.1016/j.preteyeres.2020.100920] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 10/28/2020] [Accepted: 10/31/2020] [Indexed: 12/15/2022]
Abstract
Adaptive optics scanning light ophthalmoscopy (AOSLO) allows visualization of the living human retina with exquisite single-cell resolution. This technology has improved our understanding of normal retinal structure and revealed pathophysiological details of a number of retinal diseases. Despite the remarkable capabilities of AOSLO, it has not seen the widespread commercial adoption and mainstream clinical success of other modalities developed in a similar time frame. Nevertheless, continued advancements in AOSLO hardware and software have expanded use to a broader range of patients. Current devices enable imaging of a number of different retinal cell types, with recent improvements in stimulus and detection schemes enabling monitoring of retinal function, microscopic structural changes, and even subcellular activity. This has positioned AOSLO for use in clinical trials, primarily as exploratory outcome measures or biomarkers that can be used to monitor disease progression or therapeutic response. AOSLO metrics could facilitate patient selection for such trials, to refine inclusion criteria or to guide the choice of therapy, depending on the presence, absence, or functional viability of specific cell types. Here we explore the potential of AOSLO retinal imaging by reviewing clinical applications as well as some of the pitfalls and barriers to more widespread clinical adoption.
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Affiliation(s)
- Niamh Wynne
- Department of Ophthalmology and Visual Sciences, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Joseph Carroll
- Department of Ophthalmology and Visual Sciences, Medical College of Wisconsin, Milwaukee, WI, USA; Department of Cell Biology, Neurobiology & Anatomy, Medical College of Wisconsin, Milwaukee, WI, USA; Department of Biomedical Engineering, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Jacque L Duncan
- Department of Ophthalmology, University of California, San Francisco, CA, USA.
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Boyle KC, Chen ZC, Ling T, Pandiyan VP, Kuchenbecker J, Sabesan R, Palanker D. Mechanisms of Light-Induced Deformations in Photoreceptors. Biophys J 2020; 119:1481-1488. [PMID: 33031739 PMCID: PMC7642315 DOI: 10.1016/j.bpj.2020.09.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Revised: 09/02/2020] [Accepted: 09/08/2020] [Indexed: 01/11/2023] Open
Abstract
Biological cells deform on a nanometer scale when their transmembrane voltage changes, an effect that has been visualized during the action potential using quantitative phase imaging. Similar changes in the optical path length have been observed in photoreceptor outer segments after a flash stimulus via phase-resolved optical coherence tomography. These optoretinograms reveal a fast, millisecond-scale contraction of the outer segments by tens of nanometers, followed by a slow (hundreds of milliseconds) elongation reaching hundreds of nanometers. Ultrafast measurements of the contractile response using line-field phase-resolved optical coherence tomography show a logarithmic increase in amplitude and a decreasing time to peak with increasing stimulus intensity. We present a model that relates the early receptor potential to these deformations based on the voltage-dependent membrane tension-the mechanism observed earlier in neurons and other electrogenic cells. The early receptor potential is caused by conformational changes in opsins after photoisomerization, resulting in the fractional shift of the charge across the disk membrane. Lateral repulsion of the ions on both sides of the membrane affects its surface tension and leads to its lateral expansion. Because the volume of the disks does not change on a millisecond timescale, their lateral expansion leads to an axial contraction of the outer segment. With increasing stimulus intensity and the resulting tension, the area expansion coefficient of the disk membrane also increases as thermally induced fluctuations are pulled flat, resisting further expansion. This leads to the logarithmic saturation observed in measurements as well as the peak shift in time. This imaging technique therefore relates the structural changes in the photoreceptor to the underlying neurological function of transducing light into electrical signals. Such label-free optical monitoring of neural activity using fast interferometry may be applicable not only to optoretinography but also to neuroscience in general.
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Affiliation(s)
- K C Boyle
- Department of Electrical Engineering, Stanford University, Stanford, California; Hansen Experimental Physics Laboratory, Stanford University, Stanford, California.
| | - Z C Chen
- Department of Electrical Engineering, Stanford University, Stanford, California; Hansen Experimental Physics Laboratory, Stanford University, Stanford, California
| | - T Ling
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, California; Department of Ophthalmology, Stanford University, Stanford, California
| | - V P Pandiyan
- Department of Ophthalmology, University of Washington, Seattle, Washington
| | - J Kuchenbecker
- Department of Ophthalmology, University of Washington, Seattle, Washington
| | - R Sabesan
- Department of Ophthalmology, University of Washington, Seattle, Washington.
| | - D Palanker
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, California; Department of Ophthalmology, Stanford University, Stanford, California.
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68
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Pandiyan VP, Jiang X, Maloney-Bertelli A, Kuchenbecker JA, Sharma U, Sabesan R. High-speed adaptive optics line-scan OCT for cellular-resolution optoretinography. BIOMEDICAL OPTICS EXPRESS 2020; 11:5274-5296. [PMID: 33014614 PMCID: PMC7510866 DOI: 10.1364/boe.399034] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 08/05/2020] [Accepted: 08/19/2020] [Indexed: 05/15/2023]
Abstract
Optoretinography-the non-invasive, optical imaging of light-induced functional activity in the retina-stands to provide a critical biomarker for testing the safety and efficacy of new therapies as well as their rapid translation to the clinic. Optical phase change in response to light, as readily accessible in phase-resolved OCT, offers a path towards all-optical imaging of retinal function. However, typical human eye motion adversely affects phase stability. In addition, recording fast light-induced retinal events necessitates high-speed acquisition. Here, we introduce a high-speed line-scan spectral domain OCT with adaptive optics (AO), aimed at volumetric imaging and phase-resolved acquisition of retinal responses to light. By virtue of parallel acquisition of an entire retinal cross-section (B-scan) in a single high-speed camera frame, depth-resolved tomograms at speeds up to 16 kHz were achieved with high sensitivity and phase stability. To optimize spectral and spatial resolution, an anamorphic detection paradigm was introduced, enabling improved light collection efficiency and signal roll-off compared to traditional methods. The benefits in speed, resolution and sensitivity were exemplified in imaging nanometer-millisecond scale light-induced optical path length changes in cone photoreceptor outer segments. With 660 nm stimuli, individual cone responses readily segregated into three clusters, corresponding to long, middle, and short-wavelength cones. Recording such optoretinograms on spatial scales ranging from individual cones, to 100 µm-wide retinal patches offers a robust and sensitive biomarker for cone function in health and disease.
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Affiliation(s)
- Vimal Prabhu Pandiyan
- Department of Ophthalmology, University of Washington School of Medicine, Seattle, WA 98109, USA
| | - Xiaoyun Jiang
- Department of Ophthalmology, University of Washington School of Medicine, Seattle, WA 98109, USA
| | - Aiden Maloney-Bertelli
- Department of Ophthalmology, University of Washington School of Medicine, Seattle, WA 98109, USA
| | - James A Kuchenbecker
- Department of Ophthalmology, University of Washington School of Medicine, Seattle, WA 98109, USA
| | - Utkarsh Sharma
- Catapult Sky LLC, 34116 Blue Heron Dr, Solon, OH 44139, USA
| | - Ramkumar Sabesan
- Department of Ophthalmology, University of Washington School of Medicine, Seattle, WA 98109, USA
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