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Messner A, Aranha dos Santos V, Puchner S, Stegmann H, Schlatter A, Schmidl D, Leitgeb R, Schmetterer L, Werkmeister RM. The Impact of Photopigment Bleaching on the Human Rod Photoreceptor Subretinal Space Measured Via Optical Coherence Tomography. Invest Ophthalmol Vis Sci 2024; 65:20. [PMID: 38470325 PMCID: PMC10941995 DOI: 10.1167/iovs.65.3.20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Accepted: 02/27/2024] [Indexed: 03/13/2024] Open
Abstract
Purpose The purpose of this study was to investigate rod photopigment bleaching-driven intrinsic optical signals (IOS) in the human outer retina and its measurement repeatability based on a commercial optical coherence tomography (OCT) platform. Methods The optical path length of the rod photoreceptor subretinal space (SRS), that is, the distance between signal bands of rod outer segment tips and retinal pigment epithelium, was measured in 15 healthy subjects in ambient light and during a long-duration bleaching white-light exposure. Results On 2 identical study days (day 1 and day 2 [D1 and D2]), light stimulation resulted in a significant decrease in rod SRS by 21.3 ± 7.6% and 19.8 ± 8.5% (both P < 0.001), respectively. The test-retest reliability of the SRS maximum change of an individual subject was moderate for single measures (intraclass correlation coefficient [ICC] = 0.730, 95% confidence interval [CI] = 0.376, 0.900, P < 0.001) and good for average measures (ICC = 0.844, 95% CI = 0.546, 0.947, P < 0.001). The mean area under the stimulus response curve with values of 14.8 ± 9.4 and 15.5 ± 7.5 µm × minutes (P = 0.782) showed excellent agreement between the stimulus response on D1 and D2. Intermittent dark adaptation of the retina led to an initial increase of the SRS by 6.1% (P = 0.018) and thereafter showed a decrease toward baseline, despite continued dark adaptation. Conclusions The data indicate the potential of commercial OCT in measuring slow IOS in the outer retina suggesting that the rod SRS could serve as a biomarker for photoreceptor function. The presented approach could provide an easily implementable clinical tool for the early detection of diseases affecting photoreceptor health.
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Affiliation(s)
- Alina Messner
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
- Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
| | | | - Stefan Puchner
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Hannes Stegmann
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Andreas Schlatter
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
- Vienna Institute for Research in Ocular Surgery (VIROS), Department of Ophthalmology, Hanusch Hospital, Vienna, Austria
| | - Doreen Schmidl
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Rainer Leitgeb
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Leopold Schmetterer
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
- Singapore Eye Research Institute, The Academia, Singapore, Singapore
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, Singapore, Singapore
- SERI-NTU Advanced Ocular Engineering (STANCE), Singapore, Singapore
- Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Medical School, Singapore
| | - René M. Werkmeister
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
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Fasih-Ahmad S, Wang Z, Mishra Z, Vatanatham C, Clark ME, Swain TA, Curcio CA, Owsley C, Sadda SR, Hu ZJ. Potential Structural Biomarkers in 3D Images Validated by the First Functional Biomarker for Early Age-Related Macular Degeneration - ALSTAR2 Baseline. Invest Ophthalmol Vis Sci 2024; 65:1. [PMID: 38300559 PMCID: PMC10846345 DOI: 10.1167/iovs.65.2.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2024] Open
Abstract
Purpose Lack of valid end points impedes developing therapeutic strategies for early age-related macular degeneration (AMD). Delayed rod-mediated dark adaptation (RMDA) is the first functional biomarker for incident early AMD. The relationship between RMDA and the status of outer retinal bands on optical coherence tomography (OCT) have not been well defined. This study aims to characterize these relationships in early and intermediate AMD. Methods Baseline data from 476 participants was assessed including eyes with early AMD (n = 138), intermediate AMD (n = 101), and normal aging (n = 237). Participants underwent volume OCT imaging of the macula and rod intercept time (RIT) was measured. The ellipsoid zone (EZ) and interdigitation zone (IZ) on all OCT B-scans of the volumes were segmented. The area of detectable EZ and IZ, and mean thickness of IZ within the Early Treatment Diabetic Retinopathy Study (ETDRS) grid were computed and associations with RIT were assessed by Spearman's correlation coefficient and age adjusted. Results Delayed RMDA (longer RIT) was most strongly associated with less preserved IZ area (r = -0.591; P < 0.001), followed by decreased IZ thickness (r = -0.434; P < 0.001), and EZ area (r = -0.334; P < 0.001). This correlation between RIT and IZ integrity was not apparent when considering normal eyes alone within 1.5 mm of the fovea. Conclusions RMDA is correlated with the status of outer retinal bands in early and intermediate AMD eyes, particularly, the status of the IZ. This correlation is consistent with a previous analysis of only foveal B-scans and is biologically plausible given that retinoid availability, involving transfer at the interface attributed to the IZ, is rate-limiting for RMDA.
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Affiliation(s)
| | - Ziyuan Wang
- Doheny Eye Institute, Pasadena, California, United States
| | - Zubin Mishra
- Doheny Eye Institute, Pasadena, California, United States
| | | | - Mark E Clark
- Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Thomas A Swain
- Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
- Epidemiology, School of Public Health, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Christine A Curcio
- Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Cynthia Owsley
- Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
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Lindell M, Kar D, Sedova A, Kim YJ, Packer OS, Schmidt-Erfurth U, Sloan KR, Marsh M, Dacey DM, Curcio CA, Pollreisz A. Volumetric Reconstruction of a Human Retinal Pigment Epithelial Cell Reveals Specialized Membranes and Polarized Distribution of Organelles. Invest Ophthalmol Vis Sci 2023; 64:35. [PMID: 38133501 PMCID: PMC10746928 DOI: 10.1167/iovs.64.15.35] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Accepted: 11/04/2023] [Indexed: 12/23/2023] Open
Abstract
Purpose Despite the centrality of the retinal pigment epithelium (RPE) in vision and retinopathy our picture of RPE morphology is incomplete. With a volumetric reconstruction of human RPE ultrastructure, we aim to characterize major membranous features including apical processes and their interactions with photoreceptor outer segments, basolateral infoldings, and the distribution of intracellular organelles. Methods A parafoveal retinal sample was acquired from a 21-year-old male organ donor. With serial block-face scanning electron microscopy, a tissue volume from the inner-outer segment junction to basal RPE was captured. Surface membranes and complete internal ultrastructure of an individual RPE cell were achieved with a combination of manual and automated segmentation methods. Results In one RPE cell, apical processes constitute 69% of the total cell surface area, through a dense network of over 3000 terminal branches. Single processes contact several photoreceptors. Basolateral infoldings facing the choriocapillaris resemble elongated filopodia and comprise 22% of the cell surface area. Membranous tubules and sacs of endoplasmic reticulum represent 20% of the cell body volume. A dense basal layer of mitochondria extends apically to partly overlap electron-dense pigment granules. Pores in the nuclear envelope form a distinct pattern of rows aligned with chromatin. Conclusions Specialized membranes at the apical and basal side of the RPE cell body involved in intercellular uptake and transport represent over 90% of the total surface area. Together with the polarized distribution of organelles within the cell body, these findings are relevant for retinal clinical imaging, therapeutic approaches, and disease pathomechanisms.
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Affiliation(s)
- Maximilian Lindell
- Department of Ophthalmology, Medical University of Vienna, Vienna, Austria
| | - Deepayan Kar
- Department of Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Aleksandra Sedova
- Department of Ophthalmology, Medical University of Vienna, Vienna, Austria
| | - Yeon Jin Kim
- Department of Biological Structure, University of Washington, Seattle, Washington, United States
| | - Orin S. Packer
- Department of Biological Structure, University of Washington, Seattle, Washington, United States
| | | | - Kenneth R. Sloan
- Department of Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Mike Marsh
- Object Research Systems, Montreal, Quebec, Canada
| | - Dennis M. Dacey
- Department of Biological Structure, University of Washington, Seattle, Washington, United States
| | - Christine A. Curcio
- Department of Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Andreas Pollreisz
- Department of Ophthalmology, Medical University of Vienna, Vienna, Austria
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Mullin NK, Voigt AP, Boese EA, Liu X, Stone EM, Tucker BA, Mullins RF. Transcriptomic and Chromatin Accessibility Analysis of the Human Macular and Peripheral Retinal Pigment Epithelium at the Single-Cell Level. THE AMERICAN JOURNAL OF PATHOLOGY 2023; 193:1750-1761. [PMID: 36775060 PMCID: PMC10616710 DOI: 10.1016/j.ajpath.2023.01.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 01/12/2023] [Accepted: 01/26/2023] [Indexed: 02/12/2023]
Abstract
Some human retinal diseases are characterized by pathology that is restricted to specific cell types and to specific regions of the eye. Several disease entities either selectively affect or spare the macula, the retina region at the center of the posterior pole. Photoreceptor cells in the macula are involved in high-acuity vision and require metabolic support from non-neuronal cell types. Some macular diseases involve the retinal pigment epithelium (RPE), an epithelial cell layer with several metabolic-support functions essential for the overlying photoreceptors. In the current study, the ways in which RPE confers region-specific disease susceptibility were determined by examining heterogeneity within RPE tissue from human donors. RPE nuclei from the macular and peripheral retina were profiled using joint single-nucleus RNA and ATAC sequencing. The expression of several genes differed between macular and peripheral RPE. Region-specific ATAC peaks were found, suggesting regulatory elements used exclusively by macular or peripheral RPE. Across anatomic regions, subpopulations of RPE were identified that appeared to have differential levels of expression of visual cycle genes. Finally, loci associated with age-related macular degeneration were examined for a better understanding of RPE-specific disease phenotypes. These findings showed variations in the regulation of gene expression in the human RPE by region and subpopulation, and provide a source for a better understanding of the molecular basis of macular disease.
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Affiliation(s)
- Nathaniel K Mullin
- Institute for Vision Research, University of Iowa, Iowa City, Iowa; Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, Iowa; Medical Scientist Training Program, University of Iowa, Iowa City, Iowa
| | - Andrew P Voigt
- Institute for Vision Research, University of Iowa, Iowa City, Iowa; Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, Iowa; Medical Scientist Training Program, University of Iowa, Iowa City, Iowa
| | - Erin A Boese
- Institute for Vision Research, University of Iowa, Iowa City, Iowa; Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, Iowa
| | - Xiuying Liu
- Institute for Vision Research, University of Iowa, Iowa City, Iowa; Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, Iowa
| | - Edwin M Stone
- Institute for Vision Research, University of Iowa, Iowa City, Iowa; Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, Iowa
| | - Budd A Tucker
- Institute for Vision Research, University of Iowa, Iowa City, Iowa; Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, Iowa
| | - Robert F Mullins
- Institute for Vision Research, University of Iowa, Iowa City, Iowa; Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, Iowa.
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5
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Fasih-Ahmad S, Wang Z, Mishra Z, Vatanatham C, Clark ME, Swain TA, Curcio CA, Owsley C, Sadda SR, Hu ZJ. Potential Structural Biomarkers in 3D Images Validated by the First Functional Biomarker for Early Age-Related Macular Degeneration - ALSTAR2 Baseline. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.09.10.23295309. [PMID: 37745353 PMCID: PMC10516097 DOI: 10.1101/2023.09.10.23295309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/26/2023]
Abstract
Purpose While intermediate and late age-Related Macular Degeneration (AMD) have been widely investigated, rare studies were focused on the pathophysiologic mechanism of early AMD. Delayed rod-mediated dark adaptation (RMDA) is the first functional biomarker for incident early AMD. The status of outer retinal bands on optical coherence tomography (OCT) may be potential imaging biomarkers and the purpose is to investigate the hypothesis that the integrity of interdigitation zone (IZ) may provide insight into the health of photoreceptors and retinal pigment epithelium (RPE) in early AMD. Methods We establish the structure-function relationship between ellipsoid zone (EZ) integrity and RMDA, and IZ integrity and RMDA in a large-scale OCT dataset from eyes with normal aging (n=237), early AMD (n=138), and intermediate AMD (n=101) by utilizing a novel deep-learning-derived algorithm with manual correction when needed to segment the EZ and IZ on OCT B-scans (57,596 B-scans), and utilizing the AdaptDx device to measure RMDA. Results Our data demonstrates that slower RMDA is associated with less preserved EZ (r = -0.334; p<0.001) and IZ area (r = -0.591; p<0.001), and decreased IZ thickness (r = -0.434; p<0.001). These associations are not apparent when considering normal eyes alone. Conclusions The association with IZ area and RMDA in large-scale data is biologically plausible because retinoid availability and transfer at the interface attributed to IZ is rate-limiting for RMDA. This study supports the hypothesis that the IZ integrity provides insight into the health of photoreceptors and RPE in early AMD and is a potential new imaging biomarker.
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Bell BA, Kaul C, Dunaief JL, Hollyfield JG, Bonilha VL. A comparison of optophysiological biomarkers of photoreceptor stress and phototoxicity in BALB/cJ, B6 (Cg)-Tyrc-2J/J, and C57Bl/6J mouse strains. FRONTIERS IN OPHTHALMOLOGY 2023; 3:1128311. [PMID: 38689597 PMCID: PMC11057998 DOI: 10.3389/fopht.2023.1128311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/02/2024]
Abstract
Ophthalmic imaging instruments, including the confocal scanning laser ophthalmoscope and spectral-domain optical coherence tomography system, originally intended for revealing ocular microstructures in the human eye, have been deployed by vision researchers to evaluate the eyes of numerous small and large animal species for more than two decades. In this study, we have used these two instruments to obtain imaging data sequentially from the retinas of three prominent, widely used experimental mouse models to document changes induced by two contrasting vivarium lighting conditions. Mice studied include albino BALB/cJ and B6(Cg)-Tyrc-2J/J and pigmented C57Bl/6J. Mice were reared under dim light conditions until ~8 weeks of age where they underwent baseline imaging. Following, mice were returned to the dim vivarium or relocated to the top rack cage position in a standard vivarium. Mice were then followed for several months by ocular imaging to catalog the retinal dynamics as a function of long-term dim vs. elevated, standard vivarium lighting exposure levels. Upon exposure to elevated light levels, B6(Cg)-Tyrc-2J/J underwent similar changes as BALB/cJ in regard to photoreceptor outer segment shortening, photoreceptor layer proximal aspect hyperreflective changes, and the development of retinal infoldings and autofluorescent sub-retinal inflammatory monocyte infiltrate. Noteworthy, however, is that infoldings and infiltrate occurred at a slower rate of progression in B6(Cg)-Tyrc-2J/J vs. BALB/cJ. The photoreceptor outer nuclear layer thickness of BALB/cJ degenerated steadily following elevated light onset. In contrast, B6(Cg)-Tyrc-2J/J degeneration was unremarkable for many weeks before experiencing a noticeable change in the rate of degeneration that was concomitant with a plateau and decreasing trend in number of retinal infoldings and monocyte infiltrate. Pathological changes in C57Bl/6J mice were unremarkable for all imaging biomarkers assessed with exception to autofluorescent sub-retinal inflammatory monocyte infiltrate, which showed significant accumulation in dim vs. elevated light exposed mice following ~1 year of observation. These data were evaluated using Spearman's correlation and Predictive Power Score matrices to determine the best imaging optophysiological biomarkers for indicating vivarium light stress and light-induced photoreceptor degeneration. This study suggests that changes in proximal aspect hyperreflectivity, outer segment shortening, retinal infoldings and autofluorescent sub-retinal inflammatory monocyte infiltrate are excellent indicators of light stress and light-induced degeneration in albino B6(Cg)-Tyrc-2J/J and BALB/cJ mouse strains.
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Affiliation(s)
- Brent A. Bell
- Scheie Eye Institute and Department of Ophthalmology, University of Pennsylvania, Philadelphia, PA, United States
- Cole Eye Institute/Ophthalmic Research, Cleveland Clinic, Cleveland, OH, United States
| | - Charles Kaul
- Cole Eye Institute/Ophthalmic Research, Cleveland Clinic, Cleveland, OH, United States
| | - Joshua L. Dunaief
- Scheie Eye Institute and Department of Ophthalmology, University of Pennsylvania, Philadelphia, PA, United States
| | - Joe G. Hollyfield
- Cole Eye Institute/Ophthalmic Research, Cleveland Clinic, Cleveland, OH, United States
- Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, OH, United States
| | - Vera L. Bonilha
- Cole Eye Institute/Ophthalmic Research, Cleveland Clinic, Cleveland, OH, United States
- Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, OH, United States
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7
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Chauhan P, Kho AM, FitzGerald P, Shibata B, Srinivasan VJ. Subcellular Comparison of Visible-Light Optical Coherence Tomography and Electron Microscopy in the Mouse Outer Retina. Invest Ophthalmol Vis Sci 2022; 63:10. [PMID: 35943734 PMCID: PMC9379865 DOI: 10.1167/iovs.63.9.10] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose We employed in vivo, 1.0-µm axial resolution visible-light optical coherence tomography (OCT) and ex vivo electron microscopy (EM) to investigate three subcellular features in the mouse outer retina: reflectivity oscillations inner to band 1 (study 1); hyperreflective band 2, attributed to the ellipsoid zone or inner segment/outer segment (IS/OS) junction (study 2); and the hyperreflective retinal pigment epithelium (RPE) within band 4 (study 3). Methods Pigmented (C57BL/6J, n = 10) and albino (BALB/cJ, n = 3) mice were imaged in vivo. Enucleated eyes were processed for light and electron microscopy. Using well-accepted reference surfaces, we compared micrometer-scale axial reflectivity of visible-light OCT with subcellular organization, as revealed by 9449 annotated EM organelles and features across four pigmented eyes. Results In study 1, outer nuclear layer reflectivity peaks coincided with valleys in heterochromatin clump density (−0.34 ± 2.27 µm limits of agreement [LoA]). In study 2, band 2 depth on OCT and IS/OS junction depth on EM agreed (−0.57 ± 0.76 µm LoA), with both having similar distributions. In study 3, RPE electron dense organelle distribution did not agree with reflectivity in C57BL/6J mice, with OCT measures of RPE thickness exceeding those of EM (2.09 ± 0.89 µm LoA). Finally, RPE thickness increased with age in pigmented mice (slope = 0.056 µm/mo; P = 6.8 × 10−7). Conclusions Visible-light OCT bands arise from subcellular organization, enabling new measurements in mice. Quantitative OCT–EM comparisons may be confounded by hydration level, particularly in the OS and RPE. Caution is warranted in generalizing results to other species.
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Affiliation(s)
- Pooja Chauhan
- Department of Radiology, NYU Langone Health, New York, New York, United States
| | - Aaron M Kho
- Department of Biomedical Engineering, University of California Davis, Davis, California, United States
| | - Paul FitzGerald
- Department of Cell Biology and Human Anatomy, University of California Davis, Davis, California, United States
| | - Bradley Shibata
- Biological Electron Microscopy Facility, University of California Davis, Davis, California, United States
| | - Vivek J Srinivasan
- Department of Radiology, NYU Langone Health, New York, New York, United States.,Department of Biomedical Engineering, University of California Davis, Davis, California, United States.,Department of Ophthalmology, NYU Langone Health, New York, New York, United States
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Kim TH, Ma G, Son T, Yao X. Functional Optical Coherence Tomography for Intrinsic Signal Optoretinography: Recent Developments and Deployment Challenges. Front Med (Lausanne) 2022; 9:864824. [PMID: 35445037 PMCID: PMC9013890 DOI: 10.3389/fmed.2022.864824] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 03/16/2022] [Indexed: 11/13/2022] Open
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.
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Affiliation(s)
- Tae-Hoon Kim
- Richard and Loan Hill Department of Biomedical Engineering, University of Illinois at Chicago, Chicago, IL, United States
| | - Guangying Ma
- Richard and Loan Hill Department of Biomedical Engineering, University of Illinois at Chicago, Chicago, IL, United States
| | - Taeyoon Son
- Richard and Loan Hill Department of Biomedical Engineering, University of Illinois at Chicago, Chicago, IL, United States
| | - Xincheng Yao
- Richard and Loan Hill Department of Biomedical Engineering, University of Illinois at Chicago, Chicago, IL, United States
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL, United States
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9
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Zhang L, Dong R, Zawadzki RJ, Zhang P. Volumetric data analysis enabled spatially resolved optoretinogram to measure the functional signals in the living retina. JOURNAL OF BIOPHOTONICS 2022; 15:e202100252. [PMID: 34817116 PMCID: PMC8901551 DOI: 10.1002/jbio.202100252] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2021] [Revised: 10/21/2021] [Accepted: 11/22/2021] [Indexed: 05/05/2023]
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.
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Affiliation(s)
- Lijie Zhang
- School of Optoelectronic Engineering and Instrumentation Science, Dalian University of Technology, 116024, China
| | - Rongyao Dong
- School of Optoelectronic Engineering and Instrumentation Science, Dalian University of Technology, 116024, China
| | - Robert J. Zawadzki
- UC Davis Eye-Pod Small Animals Ocular Imaging Laboratory, Department of Cell Biology and Human Anatomy, University of California Davis, Davis, California, 95616, United States
- UC Davis Eye Center, Department of Ophthalmology & Vision Science, University of California Davis, Sacramento, California, 95817, United States
| | - Pengfei Zhang
- School of Optoelectronic Engineering and Instrumentation Science, Dalian University of Technology, 116024, China
- UC Davis Eye-Pod Small Animals Ocular Imaging Laboratory, Department of Cell Biology and Human Anatomy, University of California Davis, Davis, California, 95616, United States
- Correspondence: Pengfei Zhang, Dalian University of Technology, 116024, China,
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10
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Kim TH, Ding J, Yao X. Intrinsic signal optoretinography of dark adaptation kinetics. Sci Rep 2022; 12:2475. [PMID: 35169239 PMCID: PMC8847457 DOI: 10.1038/s41598-022-06562-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 02/02/2022] [Indexed: 12/13/2022] Open
Abstract
Delayed dark adaptation due to impaired rod photoreceptor homeostasis has been reported as the earliest symptom of eye diseases such as age-related macular degeneration, diabetic retinopathy, and retinitis pigmentosa. Objective measurement of dark adaptation can facilitate early diagnosis to enable prompt intervention to prevent vision loss. However, there is a lack of noninvasive methods capable of spatiotemporal monitoring of photoreceptor changes during dark adaptation. Here we demonstrate functional optical coherence tomography (OCT) for in vivo intrinsic signal optoretinography (ORG) of dark adaptation kinetics in the C57BL/6J mouse retina. Functional OCT revealed a shortening of the outer retina, a rearrangement of the cone and rod photoreceptor interdigitation zone, and a reduction in intrinsic signal amplitude at the photoreceptor inner segment ellipsoid (ISe). A strong positive correlation between the outer retinal shortening and ISe intensity reduction was also confirmed. Functional OCT of dark adaptation kinetics promises an objective method for rapid ORG assessment of physiological integrity of retinal photoreceptors.
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Affiliation(s)
- Tae-Hoon Kim
- Department of Biomedical Engineering, University of Illinois at Chicago, Chicago, IL, 60607, USA
| | - Jie Ding
- Department of Biomedical Engineering, University of Illinois at Chicago, Chicago, IL, 60607, USA
| | - Xincheng Yao
- Department of Biomedical Engineering, 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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11
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Kho AM, Srinivasan VJ. Proactive spectrometer matching for excess noise suppression in balanced visible light optical coherence tomography (OCT). OPTICS EXPRESS 2021; 29. [PMCID: PMC8970694 DOI: 10.1364/oe.439919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Supercontinuum sources for visible light spectral domain OCT (SDOCT) are noisy and often expensive. Balanced detection can reduce excess noise, but is rarely used in SDOCT. Here, we show that balanced detection can achieve effective excess noise cancellation across all depths if two linear array spectrometers are spectrally well-matched. We propose excess noise correlation matrices as tools to achieve such precise spectral matching. Using optomechanical adjustments, while monitoring noise correlations, we proactively match wavelength sampling of two different spectrometers to just a few picometers in wavelength, or 0.001% of the overall spectral range. We show that proactively-matched spectrometers can achieve an excess noise suppression of more than two orders-of-magnitude in balanced visible light OCT, outperforming simple retrospective software calibration of mismatched spectrometers. High noise suppression enables visible light OCT of the mouse retina at 70 kHz with 125 microwatts incident power, with an inexpensive, 30 MHz repetition rate supercontinuum source. Averaged images resolve the retinal pigment epithelium in a highly pigmented mouse strain.
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Affiliation(s)
- Aaron M. Kho
- Department of Biomedical Engineering, University of California Davis, Davis, California 95616, USA
| | - Vivek J. Srinivasan
- Department of Biomedical Engineering, University of California Davis, Davis, California 95616, USA
- Department of Ophthalmology and Vision Science, University of California Davis, Davis School of Medicine, Sacramento, California 96817, USA
- Department of Ophthalmology, NYU Langone Health, New York, New York 10017, USA
- Department of Radiology, NYU Langone Health, New York, New York 10016, USA
- Tech4Health Institute, NYU Langone Health, New York, New York 10010, USA
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12
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Mathis T, Vasseur V, Zuber K, Arej N, Loria O, Kodjikian L, Sennlaub F, Mauget‐Faÿsse M. Light-induced modifications of the outer retinal hyperreflective layers on spectral-domain optical coherence tomography in humans: an experimental study. Acta Ophthalmol 2021; 99:765-772. [PMID: 33393736 PMCID: PMC8596705 DOI: 10.1111/aos.14723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2019] [Revised: 11/14/2020] [Accepted: 11/23/2020] [Indexed: 11/28/2022]
Abstract
Purpose Numerous small hyperreflective dots (HRDs) can be seen within the hyporeflective layer between the ellipsoid zone (EZ) and the interdigitation zone (IZ) on C‐scan spectral‐domain optical coherence tomography (SD‐OCT) with a yet unknown variation under light conditions. The aim of this study was to explore light‐induced SD‐OCT changes in these HRDs. Methods The study subjects were randomly assigned to two groups: Group 1 experienced a dark adaptation protocol followed by intense retinal photobleaching, while Group 2, serving as the control group, was exposed to constant ambient light without any variation. The number of HRDs was automatically counted. Results Twenty healthy volunteers were prospectively included. The number of HRDs differed significantly over time (p = 0.0013). They decreased in Group 1 after dark adaptation and retinal photobleaching before returning to baseline levels 30 min later; conversely, they remained relatively constant in Group 2 throughout the study (p < 0.001). Light‐skinned subjects had less HRD than dark‐skinned subjects. Conclusion We observed light‐induced modifications in the space between the EZ and the IZ. We hypothesize that the HRDs visible in this zone correspond to melanosomes that are mobilized during the light stimulation protocol. Larger studies are recommended to further evaluate and confirm light‐induced SD‐OCT changes under physiological and pathological conditions.
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Affiliation(s)
- Thibaud Mathis
- Department of Ophthalmology Croix‐Rousse University Hospital Hospices Civils de Lyon University of Medicine Lyon 1 Lyon France
- UMR‐CNRS 5510 Matéis Lyon 1 University Lyon France
- INSERM CNRS Institut de la Vision Sorbonne University Paris France
| | - Vivien Vasseur
- Department of Ophthalmology Rothschild Foundation Paris France
| | - Kevin Zuber
- Department of Ophthalmology Rothschild Foundation Paris France
| | - Nicolas Arej
- Department of Ophthalmology Rothschild Foundation Paris France
| | - Olivier Loria
- Department of Ophthalmology Croix‐Rousse University Hospital Hospices Civils de Lyon University of Medicine Lyon 1 Lyon France
- UMR‐CNRS 5510 Matéis Lyon 1 University Lyon France
| | - Laurent Kodjikian
- Department of Ophthalmology Croix‐Rousse University Hospital Hospices Civils de Lyon University of Medicine Lyon 1 Lyon France
- UMR‐CNRS 5510 Matéis Lyon 1 University Lyon France
| | - Florian Sennlaub
- INSERM CNRS Institut de la Vision Sorbonne University Paris France
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13
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REVISED CLASSIFICATION OF THE OPTICAL COHERENCE TOMOGRAPHY OUTER RETINAL BANDS BASED ON CENTRAL SEROUS CHORIORETINOPATHY ANALYSIS. Retina 2021; 41:181-188. [PMID: 32271277 DOI: 10.1097/iae.0000000000002792] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To evaluate the optical coherence tomography (OCT) imaging findings in recent onset neurosensory retinal detachments induced by central serous chorioretinopathy and to attempt to corroborate these findings with proposed anatomical correlates. METHODS Retinal detachments due to central serous chorioretinopathy of less than 3 months' duration and the surrounding area were scanned with OCT. The imaging of the outer retinal bands was evaluated according to proposals by Cuenca et al and the IN•OCT Consensus classification. RESULTS Optical coherence tomography findings in 11 eyes (11 patients) with CSC showed that all hyperreflective bands above Band 4 were variably continuous within the outer portion of the serous detachment. We then attempted to reconcile inconsistencies in current explanations for the outer retinal bands to propose changes to the outer retinal OCT nomenclature. CONCLUSION Our patients' OCT findings support the current standard that Band 3 is an outer retinal structure and that Band 4 represents the retinal pigment epithelium/Bruch complex. Confusion exists regarding whether the interdigitation zone extends halfway up or for the full length of the outer segments, and the hyporeflective band between Bands 3 and 4 has yet to receive an appropriate term. We therefore propose a modification to the IN•OCT Consensus classification by renaming the trilaminar hyporeflective, hyperreflective, and hyporeflective bands between Bands 2 and 4 as the outer segment-interdigitation zone complex consisting of the inner, middle, and outer segment-interdigitation zone, respectively.
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14
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Zhang T, Kho AM, Yiu G, Srinivasan VJ. Visible Light Optical Coherence Tomography (OCT) Quantifies Subcellular Contributions to Outer Retinal Band 4. Transl Vis Sci Technol 2021; 10:30. [PMID: 34003965 PMCID: PMC7998011 DOI: 10.1167/tvst.10.3.30] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Purpose To use visible light optical coherence tomography (OCT) to investigate subcellular reflectivity contributions to the outermost (4th) of the retinal hyperreflective bands visualized by current clinical near-infrared (NIR) OCT. Methods Visible light OCT, with 1.0 µm axial resolution, was performed in 28 eyes of 19 human subjects (21–57 years old) without history of ocular pathology. Two foveal and three extrafoveal hyperreflective zones were consistently depicted within band 4 in all eyes. The two outermost hyperreflective bands, occasionally visualized by NIR OCT, were presumed to be the retinal pigment epithelium (RPE) and Bruch's membrane (BM). RPE thickness, BM thickness, and RPE interior reflectivity were quantified topographically across the macula. Results A method for correcting RPE multiple scattering tails was found to both improve the Gaussian goodness-of-fit for the BM intensity profile and reduce the coefficient of variation of BM thickness in vivo. No major topographical differences in macular BM thickness were noted. RPE thickness decreased with increasing eccentricity. Visible light OCT signal intensity in the RPE was weighted to the apical side and attenuated more across the RPE in the fovea than peripherally. Conclusions Morphometry of the presumed RPE and BM bands is consistent with known anatomy. Weighting of RPE reflectivity toward the apical side suggests that melanosomes are the predominant contributors to RPE backscattering and signal attenuation in young eyes. Translational Relevance By enabling morphometric analysis of the RPE and BM, visible light OCT deciphers the main reflectivity contributions to outer retinal band 4, commonly visualized by commercial OCT systems.
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Affiliation(s)
- Tingwei Zhang
- Department of Biomedical Engineering, University of California Davis, Davis, California, USA
| | - Aaron M Kho
- Department of Biomedical Engineering, University of California Davis, Davis, California, USA
| | - Glenn Yiu
- Department of Ophthalmology and Vision Science, University of California Davis, Davis School of Medicine, Sacramento, California, USA
| | - Vivek J Srinivasan
- Department of Biomedical Engineering, University of California Davis, Davis, California, USA.,Department of Ophthalmology and Vision Science, University of California Davis, Davis School of Medicine, Sacramento, California, USA.,Department of Ophthalmology, New York University Langone Health, New York, New York, USA.,Department of Radiology, New York University Langone Health, New York, New York, USA.,Tech4Health Institute, New York University Langone Health, New York, New York, USA
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15
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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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16
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Bermond K, Wobbe C, Tarau IS, Heintzmann R, Hillenkamp J, Curcio CA, Sloan KR, Ach T. Autofluorescent Granules of the Human Retinal Pigment Epithelium: Phenotypes, Intracellular Distribution, and Age-Related Topography. Invest Ophthalmol Vis Sci 2020; 61:35. [PMID: 32433758 PMCID: PMC7405767 DOI: 10.1167/iovs.61.5.35] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose The human retinal pigment epithelium (RPE) accumulates granules significant for autofluorescence imaging. Knowledge of intracellular accumulation and distribution is limited. Using high-resolution microscopy techniques, we determined the total number of granules per cell, intracellular distribution, and changes related to retinal topography and age. Methods RPE cells from the fovea, perifovea, and near-periphery of 15 human RPE flat mounts were imaged using structured illumination microscopy (SIM) and confocal fluorescence microscopy in young (≤51 years, n = 8) and older (>80 years, n = 7) donors. Using custom FIJI plugins, granules were marked with computer assistance, classified based on morphological and autofluorescence properties, and analyzed with regard to intracellular distribution, total number per cell, and granule density. Results A total of 193,096 granules in 450 RPE cell bodies were analyzed. Based on autofluorescence properties, size, and composition, the RPE granules exhibited nine different phenotypes (lipofuscin, two; melanolipofuscin, five; melanosomes, two), distinguishable by SIM. Overall, lipofuscin (low at the fovea but increases with eccentricity and age) and melanolipofuscin (equally distributed at all three locations with no age-related changes) were the major granule types. Melanosomes were under-represented due to suboptimal visualization of apical processes in flat mounts. Conclusions Low lipofuscin and high melanolipofuscin content within foveal RPE cell bodies and abundant lipofuscin at the perifovea suggest a different genesis, plausibly related to the population of overlying photoreceptors (fovea, cones only; perifovea, highest rod density). This systematic analysis provides further insight into RPE cell and granule physiology and links granule load to cell autofluorescence, providing a subcellular basis for the interpretation of clinical fundus autofluorescence.
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Miller DT, Kurokawa K. Cellular-Scale Imaging of Transparent Retinal Structures and Processes Using Adaptive Optics Optical Coherence Tomography. Annu Rev Vis Sci 2020; 6:115-148. [PMID: 32609578 PMCID: PMC7864592 DOI: 10.1146/annurev-vision-030320-041255] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
High-resolution retinal imaging is revolutionizing how scientists and clinicians study the retina on the cellular scale. Its exquisite sensitivity enables time-lapse optical biopsies that capture minute changes in the structure and physiological processes of cells in the living eye. This information is increasingly used to detect disease onset and monitor disease progression during early stages, raising the possibility of personalized eye care. Powerful high-resolution imaging tools have been in development for more than two decades; one that has garnered considerable interest in recent years is optical coherence tomography enhanced with adaptive optics. State-of-the-art adaptive optics optical coherence tomography (AO-OCT) makes it possible to visualize even highly transparent cells and measure some of their internal processes at all depths within the retina, permitting reconstruction of a 3D view of the living microscopic retina. In this review, we report current AO-OCT performance and its success in visualizing and quantifying these once-invisible cells in human eyes.
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Affiliation(s)
- Donald T Miller
- School of Optometry, Indiana University, Bloomington, Indiana 47405, USA; ,
| | - Kazuhiro Kurokawa
- School of Optometry, Indiana University, Bloomington, Indiana 47405, USA; ,
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18
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Azimipour M, Valente D, Vienola KV, Werner JS, Zawadzki RJ, Jonnal RS. Optoretinogram: optical measurement of human cone and rod photoreceptor responses to light. OPTICS LETTERS 2020; 45:4658-4661. [PMID: 32870829 PMCID: PMC7891461 DOI: 10.1364/ol.398868] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 07/21/2020] [Indexed: 05/18/2023]
Abstract
Noninvasive, objective measurement of rod function is as significant as that of cone function, and for retinal diseases such as retinitis pigmentosa and age-related macular degeneration, rod function may be a more sensitive biomarker of disease progression and efficacy of treatment than cone function. Functional imaging of single human rod photoreceptors, however, has proven difficult because their small size and rapid functional response pose challenges for the resolution and speed of the imaging system. Here, we describe light-evoked, functional responses of human rods and cones, measured noninvasively using a synchronized adaptive optics optical coherence tomography (OCT) and scanning light ophthalmoscopy (SLO) system. The higher lateral resolution of the SLO images made it possible to confirm the identity of rods in the corresponding OCT volumes.
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Affiliation(s)
- Mehdi Azimipour
- Vision Science and Advanced Retinal Imaging Laboratory (VSRI), Department of Ophthalmology and Vision Science, UC Davis Eye Center, Sacramento, California 95817, USA
| | - Denise Valente
- Vision Science and Advanced Retinal Imaging Laboratory (VSRI), Department of Ophthalmology and Vision Science, UC Davis Eye Center, Sacramento, California 95817, USA
| | - Kari V. Vienola
- Vision Science and Advanced Retinal Imaging Laboratory (VSRI), Department of Ophthalmology and Vision Science, UC Davis Eye Center, Sacramento, California 95817, USA
| | - John S. Werner
- Vision Science and Advanced Retinal Imaging Laboratory (VSRI), Department of Ophthalmology and Vision Science, UC Davis Eye Center, Sacramento, California 95817, USA
| | - Robert J. Zawadzki
- Vision Science and Advanced Retinal Imaging Laboratory (VSRI), Department of Ophthalmology and Vision Science, UC Davis Eye Center, Sacramento, California 95817, USA
- EyePod Small Animal Ocular Imaging Laboratory, Department of Cell Biology and Human Anatomy, University of California Davis, Davis, California 95616, USA
| | - Ravi S. Jonnal
- Vision Science and Advanced Retinal Imaging Laboratory (VSRI), Department of Ophthalmology and Vision Science, UC Davis Eye Center, Sacramento, California 95817, USA
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19
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Pollreisz A, Neschi M, Sloan KR, Pircher M, Mittermueller T, Dacey DM, Schmidt-Erfurth U, Curcio CA. Atlas of Human Retinal Pigment Epithelium Organelles Significant for Clinical Imaging. Invest Ophthalmol Vis Sci 2020; 61:13. [PMID: 32648890 PMCID: PMC7425708 DOI: 10.1167/iovs.61.8.13] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2020] [Accepted: 04/27/2020] [Indexed: 02/07/2023] Open
Abstract
Purpose To quantify organelles impacting imaging in the cell body and intact apical processes of human retinal pigment epithelium (RPE), including melanosomes, lipofuscin-melanolipofuscin (LM), mitochondria, and nuclei. Methods A normal perifovea of a 21-year-old white male was preserved after rapid organ recovery. An aligned image stack was generated using serial block-face scanning electron microscopy and was annotated by expert readers (TrakEM, ImageJ). Acquired measures included cell body and nuclear volume (n = 17); organelle count in apical processes (n = 17) and cell bodies (n = 8); distance of cell body organelles along a normalized apical-basal axis (n = 8); and dimensions of organelle-bounding boxes in apical processes in selected subsamples of cell bodies and apical processes. Results In 2661 sections through 17 cells, apical processes contained 65 ± 24 melanosomes in mononucleate (n = 15) and 131 ± 28 in binucleate cells (n = 2). Cell bodies contained 681 ± 153 LM and 734 ± 170 mitochondria. LM was excluded from the basal quartile, and mitochondria from the apical quartile. Lengths of melanosomes, LM, and mitochondria, respectively were 2305 ± 528, 1320 ± 574, and 1195 ± 294 nm. The ratio of cell body to nucleus volume was 4.6 ± 0.4. LM and mitochondria covered 75% and 63%, respectively, of the retinal imaging plane. Conclusions Among RPE signal sources for optical coherence tomography, LM and mitochondria are the most numerous reflective cell body organelles. These and our published data show that most melanosomes are in apical processes. Overlapping LM and previously mitochondria cushions may support multiple reflective bands in cell bodies. This atlas of subcellular reflectivity sources can inform development of advanced optical coherence tomography technologies.
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Affiliation(s)
- Andreas Pollreisz
- Department of Ophthalmology, Medical University of Vienna, Vienna, Austria
| | - Martina Neschi
- Department of Ophthalmology, Medical University of Vienna, Vienna, Austria
| | - Kenneth R. Sloan
- Department of Ophthalmology and Visual Sciences, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
- Department of Computer Science, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Michael Pircher
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | | | - Dennis M. Dacey
- Department of Biologic Structure, University of Washington, Seattle, Washington, United States
| | | | - Christine A. Curcio
- Department of Ophthalmology and Visual Sciences, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
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20
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Öncül H, Ayhan E. Retinal nerve fiber layer, retinal pigment epithelium, and choroidal thickness in vitiligo patients. J Cosmet Dermatol 2020; 19:3032-3037. [PMID: 32515874 DOI: 10.1111/jocd.13367] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 02/23/2020] [Accepted: 02/25/2020] [Indexed: 11/28/2022]
Abstract
BACKGROUND Vitiligo is one of the common pigmentary disorders affecting the ocular structures. AIM To determine the retinal nerve fiber layer (RNFL), retinal pigment epithelium (RPE), and choroidal thickness (CT) in vitiligo patients and to evaluate the relationship between choroidal thickness and vitiligo subtypes. METHODS The right eyes of 106 participants (51 vitiligo, 55 nonvitiligo) were included in the study. All of the participants underwent detailed eye examinations and spectral-domain optical coherence tomography (SD-OCT) examinations. CT was measured manually with enhanced depth imaging optical coherence tomography (Edi-OCT) (subfoveal [SubF], nasal n500 µm [N1], n1500 µm [N2]), and temporal (t500 µm [T1], t1500 µm [T2]). RESULTS In vitiligo patients, CT values were significantly lower in the SubF, N1, N2, T1, and T2 areas compared to the control group (P = .001, P = .011, P = .002, P = .005, P ˂ .001, respectively). Periorbital involvement did not affect CT (P = .355, P = .746, P = .443, P = .633, P = .558, respectively). However, in patients with periorbital region involvement, the CT was significantly reduced if the lesion had a universal character (P ˂ .001, P = .001, P = .011, P ˂ .001, P = .002, respectively). It was observed that RPE thickness decreased in vitiligo, but this difference was not statistically significant (P = .140). RNFL thickness was unaffected in all quadrants. A positive correlation (r = .286, r = .280, respectively) was observed between the Vitiligo Area Severity Index (VASI) and age and disease duration. A negative correlation (r = -.360, r = -.316, r = -.315, r = -.313, respectively) was found in the CT of the SubF, N1, N2, T1, and T2 areas. CONCLUSION Vitiligo patients should be closely monitored for possible posterior ocular segment disorders.
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Affiliation(s)
- Hasan Öncül
- Department of Ophthalmology, University of Health Sciences Gazi Yaşargil Education Research Hospital, Diyarbakir, Turkey
| | - Erhan Ayhan
- Department of Dermatology, University of Health Sciences Gazi Yaşargil Education Research Hospital, Diyarbakir, Turkey
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21
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Lavaud A, Soukup P, Martin L, Hartnack S, Pot S. Spectral Domain Optical Coherence Tomography in Awake Rabbits Allows Identification of the Visual Streak, a Comparison with Histology. Transl Vis Sci Technol 2020; 9:13. [PMID: 32821485 PMCID: PMC7401941 DOI: 10.1167/tvst.9.5.13] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 02/13/2020] [Indexed: 12/20/2022] Open
Abstract
Purpose To evaluate visual streak (VS) identification on spectral-domain optical coherence tomography (SD-OCT) scans in awake rabbits. To report thickness measurements in the VS and adjacent retina on OCT B-scans and histologic sections and to assess inter-method bias, precision and repeatability between OCT and histology. Methods Vertical SD-OCT B-scan images through the optic nerve head and VS were acquired from 16 awake, ophthalmologically healthy experimental rabbits. Scans were acquired from both eyes, which were later enucleated and processed for light microscopy. Inner retina, inner nuclear layer, outer nuclear layer, outer retina (OR) and photoreceptor outer segment (PROS) thickness were measured on OCT images and digitalized microscopy slides in- and outside of the VS, and compared using linear mixed effects models. Results Both SD-OCT and histology allowed retinal layer identification and measurement. On OCT, OR and PROS were thickest in the central VS and thinnest outside the VS. Histology mirrored OCT results for central outer retinal layers but shows discrepancies for other layers likely because of postmortem processing artifacts. The method comparison demonstrated better repeatability for OCT measurements compared with histology. Conclusions Increased OR and PROS thickness compared with the adjacent retina allowed identification of the VS on SD-OCT in awake rabbits. OCT allows measurements devoid of processing artifacts in contrast to histology. Translational Relevance SD-OCT is possible in awake rabbits. Easy and reliable identification of the VS may facilitate the positioning and use of rabbits as model species in human macular and generalized retinal disease research.
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Affiliation(s)
- Arnold Lavaud
- Ophthalmology Section, Equine Department, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
| | - Petr Soukup
- Ophthalmology Section, Equine Department, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
| | - Louise Martin
- Clinic for Zoo Animals, Exotic Pets and Wildlife, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
| | - Sonja Hartnack
- Section of Epidemiology, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
| | - Simon Pot
- Ophthalmology Section, Equine Department, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
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22
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Rogers CS, Astrop TI, Webb SM, Ito S, Wakamatsu K, McNamara ME. Synchrotron X-ray absorption spectroscopy of melanosomes in vertebrates and cephalopods: implications for the affinity of Tullimonstrum. Proc Biol Sci 2019; 286:20191649. [PMID: 31640518 DOI: 10.1098/rspb.2019.1649] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Screening pigments are essential for vision in animals. Vertebrates use melanins bound in melanosomes as screening pigments, whereas cephalopods are assumed to use ommochromes. Preserved eye melanosomes in the controversial fossil Tullimonstrum (Mazon Creek, IL, USA) are partitioned by size and/or shape into distinct layers. These layers resemble tissue-specific melanosome populations considered unique to the vertebrate eye. Here, we show that extant cephalopod eyes also show tissue-specific size- and/or shape-specific partitioning of melanosomes; these differ from vertebrate melanosomes in the relative abundance of trace metals and in the binding environment of copper. Chemical signatures of melanosomes in the eyes of Tullimonstrum more closely resemble those of modern cephalopods than those of vertebrates, suggesting that an invertebrate affinity for Tullimonstrum is plausible. Melanosome chemistry may thus provide insights into the phylogenetic affinities of enigmatic fossils where melanosome size and/or shape are equivocal.
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Affiliation(s)
- Christopher S Rogers
- School of Biological, Earth and Environmental Sciences, University College Cork, Distillery Fields, North Mall, Cork T23 TK30, Republic of Ireland
| | - Timothy I Astrop
- School of Biological, Earth and Environmental Sciences, University College Cork, Distillery Fields, North Mall, Cork T23 TK30, Republic of Ireland
| | - Samuel M Webb
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA
| | - Shosuke Ito
- Department of Chemistry, Fujita Health University School of Health Sciences, Toyoake, Aichi 470-1192, Japan
| | - Kazumasa Wakamatsu
- Department of Chemistry, Fujita Health University School of Health Sciences, Toyoake, Aichi 470-1192, Japan
| | - Maria E McNamara
- School of Biological, Earth and Environmental Sciences, University College Cork, Distillery Fields, North Mall, Cork T23 TK30, Republic of Ireland
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Curcio CA, Sparrow JR, Bonilha VL, Pollreisz A, Lujan BJ. Re: Cuenca et al.: Cellular characterization of OCT and outer retinal bands using specific immunohistochemistry markers and clinical implications (Ophthalmology. 2018;125;407-422). Ophthalmology 2019; 125:e47-e48. [PMID: 29935676 DOI: 10.1016/j.ophtha.2018.02.031] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2018] [Accepted: 02/23/2018] [Indexed: 10/28/2022] Open
Affiliation(s)
- Christine A Curcio
- Department of Ophthalmology, University of Alabama at Birmingham School of Medicine, Birmingham, Alabama.
| | - Janet R Sparrow
- Department of Ophthalmology, Columbia University Medical Center, New York, New York; Department of Pathology and Cell Biology, Columbia University Medical Center, New York, New York
| | - Vera L Bonilha
- Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, Ohio
| | - Andreas Pollreisz
- Department of Ophthalmology and Optometry, Medical University of Vienna, Vienna Austria
| | - Brandon J Lujan
- Casey Eye Institute, Oregon Health and Science University, Portland, Oregon
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Soukup P, Maloca P, Altmann B, Festag M, Atzpodien EA, Pot S. Interspecies Variation of Outer Retina and Choriocapillaris Imaged With Optical Coherence Tomography. ACTA ACUST UNITED AC 2019; 60:3332-3342. [DOI: 10.1167/iovs.18-26257] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- Petr Soukup
- Roche Pharmaceutical Research and Early Development, Pharmaceutical Sciences, Roche Innovation Center, Basel, Switzerland
- Ophthalmology Section, Equine Department, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
| | - Peter Maloca
- Institute of Molecular and Clinical Ophthalmology Basel (IOB), Basel, Switzerland
- OCTlab Research Laboratory, Department of Ophthalmology, University of Basel, Basel, Switzerland
- Moorfields Eye Hospital, London, United Kingdom
| | - Bernd Altmann
- Roche Pharmaceutical Research and Early Development, Pharmaceutical Sciences, Roche Innovation Center, Basel, Switzerland
| | - Matthias Festag
- Roche Pharmaceutical Research and Early Development, Pharmaceutical Sciences, Roche Innovation Center, Basel, Switzerland
| | - Elke-Astrid Atzpodien
- Roche Pharmaceutical Research and Early Development, Pharmaceutical Sciences, Roche Innovation Center, Basel, Switzerland
| | - Simon Pot
- Ophthalmology Section, Equine Department, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
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Liu Z, Kurokawa K, Hammer DX, Miller DT. In vivo measurement of organelle motility in human retinal pigment epithelial cells. BIOMEDICAL OPTICS EXPRESS 2019; 10:4142-4158. [PMID: 31453000 PMCID: PMC6701538 DOI: 10.1364/boe.10.004142] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 06/24/2019] [Accepted: 06/24/2019] [Indexed: 05/18/2023]
Abstract
Retinal pigment epithelial (RPE) cells are well known to play a central role in the progression of numerous retinal diseases. Changes in the structure and function of these cells thus may serve as sensitive biomarkers of disease onset. While in vivo studies have focused on structural changes, functional ones may better capture cell health owing to their more direct connection to cell physiology. In this study, we developed a method based on adaptive optics optical coherence tomography (AO-OCT) and speckle field dynamics for characterizing organelle motility in individual RPE cells. We quantified the dynamics in terms of an exponential decay time constant, the time required for the speckle field to decorrelate. Using seven normal subjects, we found the RPE speckle field to decorrelate in about 5 s. This result has two fundamental implications for future clinical use. First, it establishes a path for generating a normative baseline to which motility of diseased RPE cells can be compared. Second, it predicts an AO-OCT image acquisition time that is 36 times faster than used in our earlier report for individuating RPE cells, thus a major improvement in clinical efficacy.
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Affiliation(s)
- Zhuolin Liu
- Center for Devices and Radiological Health (CDRH), U.S. Food and Drug Administration, 10903 New Hampshire Ave, Silver Spring, MD, 20993, USA
| | - Kazuhiro Kurokawa
- School of Optometry, Indiana University, 800 East Atwater Avenue, Bloomington, IN 47405, USA
| | - Daniel X. Hammer
- Center for Devices and Radiological Health (CDRH), U.S. Food and Drug Administration, 10903 New Hampshire Ave, Silver Spring, MD, 20993, USA
| | - Donald T. Miller
- School of Optometry, Indiana University, 800 East Atwater Avenue, Bloomington, IN 47405, USA
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26
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Swept-Source OCT and Near-Infrared Reflectance Patterns in Choroidal Nevi. ACTA ACUST UNITED AC 2019; 3:429-435. [DOI: 10.1016/j.oret.2019.01.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 12/02/2018] [Accepted: 01/02/2019] [Indexed: 11/17/2022]
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Azimipour M, Migacz JV, Zawadzki RJ, Werner JS, Jonnal RS. Functional retinal imaging using adaptive optics swept-source OCT at 1.6 MHz. OPTICA 2019. [PMID: 33511257 DOI: 10.1101/420240v1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Objective optical assessment of photoreceptor function may permit earlier diagnosis of retinal disease than current methods such as perimetry, electrophysiology, and clinical imaging. In this work, we describe an adaptive optics (AO) optical coherence tomography (OCT) system designed to measure functional responses of single cones to visible stimuli. The OCT subsystem consisted of a raster-scanning Fourier-domain mode-locked laser that acquires A scans at 1.64 MHz with a center wavelength of 1063 nm and an AO system operating in closed-loop. Analysis of serial volumetric images revealed phase changes of cone photoreceptors consistent with outer segment elongation and proportional to stimulus intensity, as well as other morphological changes in the outer segment and retinal pigment epithelium.
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Affiliation(s)
- Mehdi Azimipour
- Vision Science and Advanced Retinal Imaging Laboratory (VSRI), Department of Ophthalmology and Vision Science, UC Davis Eye Center, Sacramento, California 95817, USA
| | - Justin V Migacz
- Vision Science and Advanced Retinal Imaging Laboratory (VSRI), Department of Ophthalmology and Vision Science, UC Davis Eye Center, Sacramento, California 95817, USA
| | - Robert J Zawadzki
- Vision Science and Advanced Retinal Imaging Laboratory (VSRI), Department of Ophthalmology and Vision Science, UC Davis Eye Center, Sacramento, California 95817, USA
| | - John S Werner
- Vision Science and Advanced Retinal Imaging Laboratory (VSRI), Department of Ophthalmology and Vision Science, UC Davis Eye Center, Sacramento, California 95817, USA
| | - Ravi S Jonnal
- Vision Science and Advanced Retinal Imaging Laboratory (VSRI), Department of Ophthalmology and Vision Science, UC Davis Eye Center, Sacramento, California 95817, USA
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28
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Azimipour M, Migacz JV, Zawadzki RJ, Werner JS, Jonnal RS. Functional retinal imaging using adaptive optics swept-source OCT at 1.6 MHz. OPTICA 2019; 6:300-303. [PMID: 33511257 PMCID: PMC7839998 DOI: 10.1364/optica.6.000300] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Accepted: 02/05/2019] [Indexed: 05/04/2023]
Abstract
Objective optical assessment of photoreceptor function may permit earlier diagnosis of retinal disease than current methods such as perimetry, electrophysiology, and clinical imaging. In this work, we describe an adaptive optics (AO) optical coherence tomography (OCT) system designed to measure functional responses of single cones to visible stimuli. The OCT subsystem consisted of a raster-scanning Fourier-domain mode-locked laser that acquires A scans at 1.64 MHz with a center wavelength of 1063 nm and an AO system operating in closed-loop. Analysis of serial volumetric images revealed phase changes of cone photoreceptors consistent with outer segment elongation and proportional to stimulus intensity, as well as other morphological changes in the outer segment and retinal pigment epithelium.
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Affiliation(s)
| | | | - Robert J. Zawadzki
- Vision Science and Advanced Retinal Imaging Laboratory (VSRI), Department of Ophthalmology and Vision Science, UC Davis Eye Center, Sacramento, California 95817, USA
| | - John S. Werner
- Vision Science and Advanced Retinal Imaging Laboratory (VSRI), Department of Ophthalmology and Vision Science, UC Davis Eye Center, Sacramento, California 95817, USA
| | - Ravi S. Jonnal
- Vision Science and Advanced Retinal Imaging Laboratory (VSRI), Department of Ophthalmology and Vision Science, UC Davis Eye Center, Sacramento, California 95817, USA
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29
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Lu Y, Benedetti J, Yao X. Light-Induced Length Shrinkage of Rod Photoreceptor Outer Segments. Transl Vis Sci Technol 2018; 7:29. [PMID: 30619649 PMCID: PMC6314056 DOI: 10.1167/tvst.7.6.29] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Accepted: 10/23/2018] [Indexed: 12/20/2022] Open
Abstract
Purpose This study was designed to verify light-induced outer segment (OS) length shrinkage of rod photoreceptors and to characterize its anatomic source at disc-level resolution. Methods Frog (Rana pipiens) retinas were used for this study. Time-lapse light microscopy of freshly isolated OSs was employed to test transient rod OS changes at 10 ms temporal resolution. Histological light microscopy of dark- and light-adapted retinas was used to confirm light-induced rod OS length changes; and transmission electron microscopy (TEM) was used to quantify light-driven structural perturbation of rod OSs at disc level resolution. Results Time-lapse light microscopy images verified transient length shrinking responses in freshly isolated rod OSs. Histological light microscopy images confirmed reduced rod OS lengths in light-adapted retinas, compared to that of dark-adapted retinas. TEM images disclosed shortened inter-disc distances in light-adapted retinas compared to dark-adapted retinas. Conclusions Light-induced rod OS length shrinkage was confirmed using time-lapse light microscopy of isolated rod OSs and histological light microscopy of dark- and light-adapted retinas. TEM revealed that the rod OS length shrinkage was correlated to the light-driven decrease of the space between individual discs, not the disc thickness itself. Translational Relevance Light-induced transient rod response promises a noninvasive biomarker for early diagnosis of age-related macular degeneration and retinitis pigmentosa, in which the rod photoreceptors are known to be more vulnerable than cone photoreceptors.
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Affiliation(s)
- Yiming Lu
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA
| | - Jacopo Benedetti
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA
| | - Xincheng Yao
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA.,Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL, USA
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Lapierre-Landry M, Carroll J, Skala MC. Imaging retinal melanin: a review of current technologies. J Biol Eng 2018; 12:29. [PMID: 30534199 PMCID: PMC6280494 DOI: 10.1186/s13036-018-0124-5] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 11/22/2018] [Indexed: 11/10/2022] Open
Abstract
The retinal pigment epithelium (RPE) is essential to the health of the retina and the proper functioning of the photoreceptors. The RPE is rich in melanosomes, which contain the pigment melanin. Changes in RPE pigmentation are seen with normal aging and in diseases such as albinism and age-related macular degeneration. However, most techniques used to this day to detect and quantify ocular melanin are performed ex vivo and are destructive to the tissue. There is a need for in vivo imaging of melanin both at the clinical and pre-clinical level to study how pigmentation changes can inform disease progression. In this manuscript, we review in vivo imaging techniques such as fundus photography, fundus reflectometry, near-infrared autofluorescence imaging, photoacoustic imaging, and functional optical coherence tomography that specifically detect melanin in the retina. These methods use different contrast mechanisms to detect melanin and provide images with different resolutions and field-of-views, making them complementary to each other.
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Affiliation(s)
- Maryse Lapierre-Landry
- 1Morgridge Institute for Research, Madison, WI USA.,2Department of Biomedical Engineering, Vanderbilt University, Nashville, TN USA.,6Department of Pediatrics, Case Western Reserve University, Cleveland, OH USA
| | - Joseph Carroll
- 3Department of Cell Biology, Neurobiology & Anatomy, Medical College of Wisconsin, Milwaukee, WI USA.,4Department of Ophthalmology & Visual Sciences, Medical College of Wisconsin, Milwaukee, WI USA
| | - Melissa C Skala
- 1Morgridge Institute for Research, Madison, WI USA.,5Department of Biomedical Engineering, University of Wisconsin Madison, Madison, WI USA
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31
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Grieve K, Gofas-Salas E, Ferguson RD, Sahel JA, Paques M, Rossi EA. In vivo near-infrared autofluorescence imaging of retinal pigment epithelial cells with 757 nm excitation. BIOMEDICAL OPTICS EXPRESS 2018; 9:5946-5961. [PMID: 31065405 PMCID: PMC6490976 DOI: 10.1364/boe.9.005946] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 10/22/2018] [Accepted: 10/23/2018] [Indexed: 05/06/2023]
Abstract
We demonstrate near-infrared autofluorescence (NIRAF) imaging of retinal pigment epithelial (RPE) cells in vivo in healthy volunteers and patients using a 757 nm excitation source in adaptive optics scanning laser ophthalmoscopy (AOSLO). NIRAF excited at 757 nm and collected in an emission band from 778 to 810 nm produced a robust NIRAF signal, presumably arising from melanin, and revealed the typical hexagonal mosaic of RPE cells at most eccentricities imaged within the macula of normal eyes. Several patterns of altered NIRAF structure were seen in patients, including disruption of the NIRAF over a drusen, diffuse hyper NIRAF signal with loss of individual cell delineation in a case of non-neovascular age-related macular degeneration (AMD), and increased visibility of the RPE mosaic under an area showing loss of photoreceptors. In some participants, a superposed cone mosaic was clearly visible in the fluorescence channel at eccentricities between 2 and 6° from the fovea. This was reproducible in these participants and existed despite the use of emission filters with an optical attenuation density of 12 at the excitation wavelength, minimizing the possibility that this was due to bleed through of the excitation light. This cone signal may be a consequence of cone waveguiding on either the ingoing excitation light and/or the outgoing NIRAF emitted by fluorophores within the RPE and/or choroid and warrants further investigation. NIRAF imaging at 757 nm offers efficient signal excitation and detection, revealing structural alterations in retinal disease with good contrast and shows promise as a tool for monitoring future therapies at the level of single RPE cells.
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Affiliation(s)
- Kate Grieve
- Vision Institute and Quinze Vingts National Ophthalmology Hospital, PARIS group, 28 rue de Charenton, 75712, Paris, France
| | - Elena Gofas-Salas
- Vision Institute and Quinze Vingts National Ophthalmology Hospital, PARIS group, 28 rue de Charenton, 75712, Paris, France
- DOTA, ONERA, Université Paris Saclay F-91123 Palaisea, France
| | | | - José Alain Sahel
- Vision Institute and Quinze Vingts National Ophthalmology Hospital, PARIS group, 28 rue de Charenton, 75712, Paris, France
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Michel Paques
- Vision Institute and Quinze Vingts National Ophthalmology Hospital, PARIS group, 28 rue de Charenton, 75712, Paris, France
| | - Ethan A. Rossi
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
- Department of Bioengineering, University of Pittsburgh Swanson School of Engineering, Pittsburgh, PA 15213, USA
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32
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Yao X, Son T, Kim TH, Lu Y. Functional optical coherence tomography of retinal photoreceptors. Exp Biol Med (Maywood) 2018; 243:1256-1264. [PMID: 30482040 DOI: 10.1177/1535370218816517] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
IMPACT STATEMENT Retinal photoreceptors are the primary target of age-related macular degeneration (AMD) which is the leading cause of severe vision loss and legal blindness. An objective method for functional assessment of photoreceptor physiology can benefit early detection and better treatment evaluation of AMD and other eye diseases that are known to cause photoreceptor dysfunctions. This article summarizes in vitro study of IOS mechanisms and in vivo demonstration of IOS imaging of intact animals. Further development of the functional IOS imaging may provide a revolutionary solution to achieve objective assessment of human photoreceptors.
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Affiliation(s)
- Xincheng Yao
- 1 Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA.,2 Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Taeyoon Son
- 1 Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Tae-Hoon Kim
- 1 Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Yiming Lu
- 1 Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
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Rosencrans RF, Leslie CE, Perkins KA, Walkowski W, Gordon WC, Richards-Zawacki CL, Bazan NG, Farris HE. Quantifying the relationship between optical anatomy and retinal physiological sensitivity: A comparative approach. J Comp Neurol 2018; 526:3045-3057. [PMID: 30198557 PMCID: PMC10075234 DOI: 10.1002/cne.24531] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 07/27/2018] [Accepted: 08/27/2018] [Indexed: 02/03/2023]
Abstract
Light intensity varies 1 million-fold between night and day, driving the evolution of eye morphology and retinal physiology. Despite extensive research across taxa showing anatomical adaptations to light niches, surprisingly few empirical studies have quantified the relationship between such traits and the physiological sensitivity to light. In this study, we employ a comparative approach in frogs to determine the physiological sensitivity of eyes in two nocturnal (Rana pipiens, Hyla cinerea) and two diurnal species (Oophaga pumilio, Mantella viridis), examining whether differences in retinal thresholds can be explained by ocular and cellular anatomy. Scotopic electroretinogram (ERG) analysis of relative b-wave amplitude reveals 10- to 100-fold greater light sensitivity in nocturnal compared to diurnal frogs. Ocular and cellular optics (aperture, focal length, and rod outer segment dimensions) were assessed via the Land equation to quantify differences in optical sensitivity. Variance in retinal thresholds was overwhelmingly explained by Land equation solutions, which describe the optical sensitivity of single rods. Thus, at the b-wave, stimulus-response thresholds may be unaffected by photoreceptor convergence (which create larger, combined collecting areas). Follow-up experiments were conducted using photopic ERGs, which reflect cone vision. Under these conditions, the relative difference in thresholds was reversed, such that diurnal species were more sensitive than nocturnal species. Thus, photopic data suggest that rod-specific adaptations, not ocular anatomy (e.g., aperture and focal distance), drive scotopic thresholds differences. To the best of our knowledge, these data provide the first quantified relationship between optical and physiological sensitivity in vertebrates active in different light regimes.
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Affiliation(s)
- Robert F Rosencrans
- Neuroscience Center, Louisiana State University School of Medicine, New Orleans, Louisiana
| | - Caitlin E Leslie
- Department of Integrative Biology, University of Texas, Austin, Texas
| | - Keith A Perkins
- Neuroscience Center, Louisiana State University School of Medicine, New Orleans, Louisiana
| | - Whitney Walkowski
- Neuroscience Center, Louisiana State University School of Medicine, New Orleans, Louisiana
| | - William C Gordon
- Neuroscience Center, Louisiana State University School of Medicine, New Orleans, Louisiana.,Department of Ophthalmology, Louisiana State University School of Medicine, New Orleans, Louisiana
| | | | - Nicolas G Bazan
- Neuroscience Center, Louisiana State University School of Medicine, New Orleans, Louisiana.,Department of Ophthalmology, Louisiana State University School of Medicine, New Orleans, Louisiana
| | - Hamilton E Farris
- Neuroscience Center, Louisiana State University School of Medicine, New Orleans, Louisiana.,Department of Otorhinolaryngology, Louisiana State University School of Medicine, New Orleans, Louisiana.,Department of Cell Biology and Anatomy, Louisiana State University School of Medicine, New Orleans, Louisiana
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Lapierre-Landry M, Huckenpahler AL, Link BA, Collery RF, Carroll J, Skala MC. Imaging Melanin Distribution in the Zebrafish Retina Using Photothermal Optical Coherence Tomography. Transl Vis Sci Technol 2018; 7:4. [PMID: 30197836 PMCID: PMC6126953 DOI: 10.1167/tvst.7.5.4] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Accepted: 07/31/2018] [Indexed: 11/29/2022] Open
Abstract
Purpose To demonstrate and validate that photothermal optical coherence tomography (PT-OCT) can image melanin in the retinal pigment epithelium (RPE) and can observe light-driven melanosome translocation in the zebrafish retina. Methods A commercial spectral domain OCT system was modified to perform both OCT and PT-OCT. Four adult tyrosinase-mosaic zebrafish with varying levels of melanin expression across their retinas were imaged, and the PT-OCT signal for pigmented and nonpigmented regions were compared. Wild-type dark-adapted (n = 11 fish) and light-adapted (n = 10 fish) zebrafish were also imaged with OCT and PT-OCT. Longitudinal reflectivity and absorption profiles were generated from B-scans to compare the melanin distribution between the two groups. Results A significant increase in PT-OCT signal (P < 0.0001, Student's t-test) was observed in pigmented regions of interest (ROI) compared to nonpigmented ROIs in the tyrosinase-mosaic zebrafish, which confirms the PT-OCT signal is specific to melanin in the eye. A significant increase in PT-OCT signal intensity (P < 0.0001, Student's t-test) was also detected in the light-adapted wild-type zebrafish group compared to the dark-adapted group. Additionally, light-adapted zebrafish display more distinct melanin banding patterns than do dark-adapted zebrafish in PT-OCT B-scans. Conclusions PT-OCT can detect different levels of melanin absorption and characterize pigment distribution in the zebrafish retina, including intracellular changes due to light-driven melanosome translocation within the RPE. Translational Relevance PT-OCT could quantify changes in pigmentation that occur in retinal diseases. The functional information provided by PT-OCT may also enable a better understanding of the anatomical features within conventional OCT images.
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Affiliation(s)
- Maryse Lapierre-Landry
- Biomedical Engineering, Vanderbilt University, Nashville, TN, USA.,Morgridge Institute for Research, Madison, WI, USA
| | - Alison L Huckenpahler
- Cell Biology, Neurobiology & Anatomy, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Brian A Link
- Cell Biology, Neurobiology & Anatomy, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Ross F Collery
- Cell Biology, Neurobiology & Anatomy, Medical College of Wisconsin, Milwaukee, WI, USA.,Ophthalmology & Visual Sciences, 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
| | - Melissa C Skala
- Morgridge Institute for Research, Madison, WI, USA.,Biomedical Engineering, University of Wisconsin Madison, Madison, WI, USA
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Li Y, Zhang Y, Chen S, Vernon G, Wong WT, Qian H. Light-Dependent OCT Structure Changes in Photoreceptor Degenerative rd 10 Mouse Retina. Invest Ophthalmol Vis Sci 2018; 59:1084-1094. [PMID: 29490345 PMCID: PMC5824802 DOI: 10.1167/iovs.17-23011] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Purpose Using optical coherence tomography (OCT) to analyze the effects of light/dark adaptation in a mouse model of inherited photoreceptor degeneration (rd10), and to study dynamics of subretinal fluid during the progress of retinal degeneration. Methods rd10 and wild-type (WT) C57BL/6J mice were reared in cyclic light or darkness and imaged with Bioptigen UHR-OCT or Spectralis HRA+OCT after adaptation to either light or darkness. Results OCT images from rd10 mice were analyzed at three progressive stages of degeneration. After light-adaptation, stage I (postnatal age [P]26–29) eyes demonstrated no apparent subretinal fluid. At stage II (P32–38), subretinal fluid was present and restricted to parapapillary area, while at stage III (P44–45) extensive subretinal fluid was present across many retinal areas. Following overnight dark-adaptation, WT eyes showed a large reduction in outer retinal thickness (4.6 ± 1.4 μm, n = 16), whereas this change was significantly smaller in stage I rd10 eyes (1.5 ± 0.5 μm, n = 14). In stage II rd10 eyes, dark-adaptation significantly reduced the extent of subretinal fluid, with the amount of reduction correlating with the amount of fluid pre-existing in the light-adapted state. However, dark-adaptation did not significantly alter the amount of subretinal fluid observed in stage III rd10 mice. In addition, dark-rearing of rd10 mice from P6 to P30 slowed retinal degeneration. Conclusions Visual experience in the form of light/dark adaptation exerts a significant effect on outer retinal structure in the context of photoreceptor degeneration. This effect may arise from light-dependent alterations in fluid transport across the RPE monolayer, and promote photoreceptor survival as induced by dark-rearing.
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Affiliation(s)
- Yichao Li
- Visual Function Core, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Yikui Zhang
- Unit on Neuron-Glia Interactions in Retinal Disease, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Sonia Chen
- Visual Function Core, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Gregory Vernon
- Visual Function Core, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Wai T Wong
- Unit on Neuron-Glia Interactions in Retinal Disease, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Haohua Qian
- Visual Function Core, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
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CORRELATION BETWEEN PREOPERATIVE EN FACE OPTICAL COHERENCE TOMOGRAPHY OF PHOTORECEPTOR LAYER AND VISUAL PROGNOSIS AFTER MACULAR HOLE SURGERY. Retina 2018; 38:1220-1230. [PMID: 28613215 DOI: 10.1097/iae.0000000000001679] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To investigate the correlation between preoperative en face spectral domain optical coherence tomography findings of the photoreceptor layer with restoration of foveal microstructure and visual acuity in repaired macular holes. METHODS Medical records of 106 patients with surgically closed macular holes were retrospectively reviewed. Preoperative OCT slabs of the external limiting membrane (ELM) and ellipsoid zone (EZ) were generated using embedded tools. All patients were classified into two groups according to the presence of preoperative retinal pigment epithelium protrusion seen as hyperreflective spots in EZ slab. Visual acuity, homogenous reflectivity, and glial proliferation in the ELM and EZ slabs were followed for 12 months. RESULTS Baseline hyperreflective spots in the EZ slab was observed in 51 (48.1%) eyes. Postoperative homogenous reflectivity and glial proliferation were related to the presence of baseline hyperreflective spots. Vision improvement was significantly greater in the absence of hyperreflective spots group from 9 months after the operation. In logistic regression analysis, the area of hyperreflective spots was significantly associated with foveal homogenous reflectivity at 12 months (P = 0.004). CONCLUSION Preoperative hyperreflective spots in en face EZ slab might be indicative of functional and anatomical restoration after macular hole surgery.
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Sajdak BS, Bell BA, Lewis TR, Luna G, Cornwell GS, Fisher SK, Merriman DK, Carroll J. Assessment of Outer Retinal Remodeling in the Hibernating 13-Lined Ground Squirrel. Invest Ophthalmol Vis Sci 2018; 59:2538-2547. [PMID: 29847661 PMCID: PMC5967598 DOI: 10.1167/iovs.17-23120] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2017] [Accepted: 04/20/2018] [Indexed: 12/25/2022] Open
Abstract
Purpose We examined outer retinal remodeling of the euthermic and torpid cone-dominant 13-lined ground squirrel (13-LGS) retina using optical coherence tomography (OCT) imaging and histology. Methods Retinas and corneas of living 13-LGSs were imaged during euthermic and torpid physiological states using OCT. Retinal layer thickness was measured at the visual streak from registered and averaged vertical B-scans. Following OCT, some retinas were collected immediately for postmortem histologic comparison using light microscopy, immunofluorescence, or transmission electron microscopy. Results Compared to OCT images from euthermic retinae, OCT images of torpid retinae revealed significantly thicker inner and outer nuclear layers, as well as increases in the distances between outer retinal reflectivity bands 1 and 2, and bands 3 and 4. A significant decrease in the distance between bands 2 and 3 also was seen, alongside significant thinning of the choriocapillaris and choroid. OCT image quality was reduced in torpid eyes, partly due to significant thickening of the corneal stroma during this state. Conclusions The torpid retina of the hibernating 13-LGS undergoes structural changes that can be detected by OCT imaging. Comparisons between in vivo OCT and ex vivo histomorphometry may offer insight to the origin of hyperreflective OCT bands within the outer retina of the cone-dominant 13-LGS.
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Affiliation(s)
- Benjamin S. Sajdak
- Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Brent A. Bell
- Cole Eye Institute/Ophthalmic Research, Cleveland Clinic, Cleveland, Ohio, United States
| | - Tylor R. Lewis
- Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Gabriel Luna
- Neuroscience Research Institute, University of California Santa Barbara, Santa Barbara, California, United States
| | - Grayson S. Cornwell
- Neuroscience Research Institute, University of California Santa Barbara, Santa Barbara, California, United States
| | - Steven K. Fisher
- Neuroscience Research Institute, University of California Santa Barbara, Santa Barbara, California, United States
| | - Dana K. Merriman
- Biology & Microbiology, University of Wisconsin Oshkosh, Oshkosh, Wisconsin, United States
| | - Joseph Carroll
- Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
- Ophthalmology & Visual Sciences, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
- Biophysics, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
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Paavo M, Lee W, Merriam J, Bearelly S, Tsang S, Chang S, Sparrow JR. Intraretinal Correlates of Reticular Pseudodrusen Revealed by Autofluorescence and En Face OCT. Invest Ophthalmol Vis Sci 2017; 58:4769-4777. [PMID: 28973322 PMCID: PMC5624777 DOI: 10.1167/iovs.17-22338] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose We sought to determine whether information revealed from the reflectance, autofluorescence, and absorption properties of RPE cells situated posterior to reticular pseudodrusen (RPD) could provide insight into the origins and structure of RPD. Methods RPD were studied qualitatively by near-infrared fundus autofluorescence (NIR-AF), short-wavelength fundus autofluorescence (SW-AF), and infrared reflectance (IR-R) images, and the presentation was compared to horizontal and en face spectral domain optical coherence tomographic (SD-OCT) images. Images were acquired from 23 patients (39 eyes) diagnosed with RPD (mean age 80.7 ± 7.1 [SD]; 16 female; 4 Hispanics, 19 non-Hispanic whites). Results In SW-AF, NIR-AF, and IR-R images, fundus RPD were recognized as interlacing networks of small scale variations in IR-R and fluorescence (SW-AF, NIR-AF) intensities. Darkened foci of RPD colocalized in SW-AF and NIR-AF images, and in SD-OCT images corresponded to disturbances of the interdigitation (IZ) and ellipsoid (EZ) zones and to more pronounced hyperreflective lesions traversing photoreceptor-attributable bands in SD-OCT images. Qualitative assessment of the outer nuclear layer (ONL) revealed thinning as RPD extended radially from the outer to inner retina. In en face OCT, hyperreflective areas in the EZ band correlated topographically with hyporeflective foci at the level of the RPE. Conclusions The hyperreflective lesions corresponding to RPD in SD-OCT scans are likely indicative of degenerating photoreceptor cells. The darkened foci at positions of RPD in NIR-AF and en face OCT images indicate changes in the RPE monolayer with the reduced NIR-AF and en face OCT signal suggesting a reduction in melanin that could be accounted for by RPE thinning.
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Affiliation(s)
- Maarjaliis Paavo
- Department of Ophthalmology, Columbia University Medical Center, New York, New York, United States
| | - Winston Lee
- Department of Ophthalmology, Columbia University Medical Center, New York, New York, United States
| | - John Merriam
- Department of Ophthalmology, Columbia University Medical Center, New York, New York, United States
| | - Srilaxmi Bearelly
- Department of Ophthalmology, Columbia University Medical Center, New York, New York, United States
| | - Stephen Tsang
- Department of Ophthalmology, Columbia University Medical Center, New York, New York, United States.,Department of Pathology and Cell Biology, Columbia University Medical Center, New York, New York, United States
| | - Stanley Chang
- Department of Ophthalmology, Columbia University Medical Center, New York, New York, United States
| | - Janet R Sparrow
- Department of Ophthalmology, Columbia University Medical Center, New York, New York, United States.,Department of Pathology and Cell Biology, Columbia University Medical Center, New York, New York, United States
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Lu CD, Lee B, Schottenhamml J, Maier A, Pugh EN, Fujimoto JG. Photoreceptor Layer Thickness Changes During Dark Adaptation Observed With Ultrahigh-Resolution Optical Coherence Tomography. Invest Ophthalmol Vis Sci 2017; 58:4632-4643. [PMID: 28898357 PMCID: PMC5596796 DOI: 10.1167/iovs.17-22171] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Purpose To examine outer retinal band changes after flash stimulus and subsequent dark adaptation with ultrahigh-resolution optical coherence tomography (UHR-OCT). Methods Five dark-adapted left eyes of five normal subjects were imaged with 3-μm axial-resolution UHR-OCT during 30 minutes of dark adaptation following 96%, 54%, 23%, and 0% full-field and 54% half-field rhodopsin bleach. We identified the ellipsoid zone inner segment/outer segment (EZ[IS/OS]), cone interdigitation zone (CIZ), rod interdigitation zone (RIZ), retinal pigment epithelium (RPE), and Bruch's membrane (BM) axial positions and generated two-dimensional thickness maps of the EZ(IS/OS) to the four bands. The average thickness over an area of the thickness map was compared against that of the dark-adapted baselines. The time-dependent thickness changes (photoresponses) were statistically compared against 0% bleach. Dark adaptometry was performed with the same bleaching protocol. Results The EZ(IS/OS)-CIZ photoresponse was significantly different at 96% (P < 0.0001) and 54% (P = 0.006) bleach. At all three bleaching levels, the EZ(IS/OS)-RIZ, -RPE, and -BM responses were significantly different (P < 0.0001). The EZ(IS/OS)-CIZ and EZ(IS/OS)-RIZ time courses were similar to the recovery of rod- and cone-mediated sensitivity, respectively, measured with dark adaptometry. The maximal EZ(IS/OS)-CIZ and EZ(IS/OS)-RIZ response magnitudes doubled from 54% to 96% bleach. Both EZ(IS/OS)-RPE and EZ(IS/OS)-BM responses resembled dampened oscillations that were graded in amplitude and duration with bleaching intensity. Half-field photoresponses were localized to the stimulated retina. Conclusions With noninvasive, near-infrared UHR-OCT, we characterized three distinct, spatially localized photoresponses in the outer retinal bands. These photoresponses have potential value as physical correlates of photoreceptor function.
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Affiliation(s)
- Chen D Lu
- Research Laboratory of Electronics and Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States
| | - ByungKun Lee
- Research Laboratory of Electronics and Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States
| | - Julia Schottenhamml
- Pattern Recognition Laboratory, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
| | - Andreas Maier
- Pattern Recognition Laboratory, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
| | - Edward N Pugh
- Departments of Physiology and Membrane Biology, and Cell Biology and Human Anatomy, School of Medicine, University of California-Davis, Davis, California, United States
| | - James G Fujimoto
- Research Laboratory of Electronics and Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States
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Li Y, Fariss RN, Qian JW, Cohen ED, Qian H. Light-Induced Thickening of Photoreceptor Outer Segment Layer Detected by Ultra-High Resolution OCT Imaging. Invest Ophthalmol Vis Sci 2017; 57:OCT105-11. [PMID: 27409460 PMCID: PMC4968769 DOI: 10.1167/iovs.15-18539] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
PURPOSE We examined if light induces changes in the retinal structure that can be observed using optical coherence tomography (OCT). METHODS Normal C57BL/6J mice (age 3-6 months) adapted to either room light (15 minutes to ∼5 hours, 50-500 lux) or darkness (overnight) were imaged using a Bioptigen UHR-OCT system. Confocal histologic images were obtained from mice killed under light- or dark-adapted conditions. RESULTS The OCT image of eyes adapted to room light exhibited significant increases (6.1 ± 0.8 μm, n = 13) in total retina thickness compared to the same eyes after overnight dark adaptation. These light-adapted retinal thickness changes occurred mainly in the outer retina, with the development of a hyporeflective band between the RPE and photoreceptor-tip layers. Histologic analysis revealed a light-evoked elongation between the outer limiting membrane and Bruch's membrane from 45.8 ± 1.7 μm in the dark (n = 5) to 52.1 ± 3.7 μm (n = 5) in the light. Light-adapted retinas showed an increase of actin staining in RPE apical microvilli at the same location as the hyporeflective band observed in OCT images. Elongation of the outer retina could be detected even with brief light exposures, increasing 2.1 ± 0.3 μm after 15 minutes (n = 9), and 4.1 ± 1.0 μm after 2 hours (n = 6). Conversely, dark-adaptation caused outer retinal shortening of 1.4 ± 0.4 μm (n = 7) and 3.0 ± 0.5 μm (n = 8) after 15 minutes and 2 hours, respectively. CONCLUSIONS Light-adaption induces an increase in the thickness of the outer retina and the appearance of a hyporeflective band in the OCT image. This is consistent with previous reports of light-induced fluid accumulation in the subretinal space.
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Affiliation(s)
- Yichao Li
- Visual Function Core National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Robert N Fariss
- Biological Imaging Core, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Jennifer W Qian
- College of Arts & Sciences, University of Virginia, Charlottesville, Virginia, United States
| | - 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, Maryland, United States
| | - Haohua Qian
- Visual Function Core National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
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Wilk MA, Huckenpahler AL, Collery RF, Link BA, Carroll J. The Effect of Retinal Melanin on Optical Coherence Tomography Images. Transl Vis Sci Technol 2017; 6:8. [PMID: 28392975 PMCID: PMC5381330 DOI: 10.1167/tvst.6.2.8] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Accepted: 02/13/2017] [Indexed: 11/24/2022] Open
Abstract
Purpose We assessed the effect of melanin on the appearance of hyperreflective outer retinal bands in optical coherence tomography (OCT) images. Methods A total of 23 normal subjects and 51 patients with albinism were imaged using the Bioptigen high-resolution spectral-domain OCT. In addition, three wild type, three albino (slc45a2b4/b4), and eight tyrosinase mosaic zebrafish were imaged with the hand-held Bioptigen Envisu R2200 OCT. To identify pigmented versus nonpigmented regions in the tyrosinase mosaic zebrafish, en face summed volume projections of the retinal pigment epithelium (RPE) were created from volume scans. Longitudinal reflectivity profiles were generated from B-scans to assess the width and maximum intensity of the RPE band in fish, or the presence of one or two RPE/Bruch's membrane (BrM) bands in humans. Results The foveal RPE/BrM appeared as two bands in 71% of locations in patients with albinism and 45% of locations in normal subjects (P = 0.0003). Pigmented zebrafish retinas had significantly greater RPE reflectance, and pigmented regions of mosaic zebrafish also had significantly broader RPE bands than all other groups. Conclusions The hyperreflective outer retinal bands in OCT images are highly variable in appearance. We showed that melanin is a major contributor to the intensity and width of the RPE band on OCT. One should use caution in extrapolating findings from OCT images of one or even a few individuals to define the absolute anatomic correlates of the hyperreflective outer retinal bands in OCT images. Translational Relevance Melanin affects the appearance of the outer retinal bands in OCT images. Use of animal models may help dissect the anatomic correlates of the complex reflective signals in OCT retinal images.
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Affiliation(s)
- Melissa A Wilk
- Department of Cell Biology, Neurobiology, & Anatomy, Medical College of Wisconsin, Milwaukee, WI, USA ; Current affiliation: HudsonAlpha Institute for Biotechnology, 601 Genome Way, Huntsville, AL, USA
| | - Alison L Huckenpahler
- Department of Cell Biology, Neurobiology, & Anatomy, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Ross F Collery
- Department of Cell Biology, Neurobiology, & Anatomy, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Brian A Link
- Department of Cell Biology, Neurobiology, & Anatomy, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Joseph Carroll
- Department of Cell Biology, Neurobiology, & Anatomy, Medical College of Wisconsin, Milwaukee, WI, USA ; Department of Ophthalmology, Medical College of Wisconsin, Milwaukee, WI, USA ; Department of Biophysics, Medical College of Wisconsin, Milwaukee, WI, USA
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Bell BA, Yuan A, Dicicco RM, Fogerty J, Lessieur EM, Perkins BD. The adult zebrafish retina: In vivo optical sectioning with Confocal Scanning Laser Ophthalmoscopy and Spectral-Domain Optical Coherence Tomography. Exp Eye Res 2016; 153:65-78. [PMID: 27720860 DOI: 10.1016/j.exer.2016.10.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 09/02/2016] [Accepted: 10/04/2016] [Indexed: 11/27/2022]
Abstract
Non-invasive imaging is an invaluable diagnostic tool in ophthalmology. Two imaging devices, the scanning laser ophthalmoscope (SLO) and spectral domain optical coherence tomography (SDOCT), emerged from the clinical realm to provide research scientists with a real-time view of ocular morphology in living animals. We utilized these two independent imaging modalities in a complementary manner to perform in vivo optical sectioning of the adult zebrafish retina. Due to the very high optical power of the zebrafish lens, the confocal depth of field is narrow, allowing for detailed en face views of specific retinal layers, including the cone mosaic. Moreover, we demonstrate that both native reflectance, as well as fluorescent features observed by SLO, can be combined with axial in-depth information obtained by SDOCT. These imaging approaches can be used to screen for ocular phenotypes and monitor retinal pathology in a non-invasive manner.
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Affiliation(s)
- Brent A Bell
- Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, OH, United States.
| | - Alex Yuan
- Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, OH, United States; Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH, United States
| | - Rose M Dicicco
- Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, OH, United States
| | - Joseph Fogerty
- Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, OH, United States
| | - Emma M Lessieur
- Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, OH, United States; Molecular Medicine PhD Program Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH, United States
| | - Brian D Perkins
- Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, OH, United States; Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH, United States
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Son T, Wang B, Thapa D, Lu Y, Chen Y, Cao D, Yao X. Optical coherence tomography angiography of stimulus evoked hemodynamic responses in individual retinal layers. BIOMEDICAL OPTICS EXPRESS 2016; 7:3151-62. [PMID: 27570706 PMCID: PMC4986822 DOI: 10.1364/boe.7.003151] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Revised: 06/08/2016] [Accepted: 06/10/2016] [Indexed: 05/05/2023]
Abstract
Blood flow changes are highly related to neural activities in the retina. It has been reported that neural activity increases when flickering light stimulation of the retina is used. It is known that blood flow changes with flickering light stimulation can be altered in patients with vascular disease and that measurement of flicker-induced vasodilatation is an easily applied tool for monitoring functional microvascular alterations. However, details of distortions in retinal neurovascular coupling associated with major eye diseases are not well understood due to the limitation of existing techniques. In this study, flickering light stimulation was applied to mouse retinas to investigate stimulus evoked hemodynamic responses in individual retinal layers. A spectral domain optical coherence tomography (OCT) angiography imaging system was developed to provide dynamic mapping of hemodynamic responses in the ganglion cell layer, inner plexiform layer, outer plexiform layer and choroid layer before, during and after flickering light stimulation. Experimental results showed hemodynamic responses with different magnitudes and time courses in individual retinal layers. We anticipate that the dynamic OCT angiography of stimulus evoked hemodynamic responses can greatly foster the study of neurovascular coupling mechanisms in the retina, promising new biomarkers for retinal disease detection and diagnosis.
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Affiliation(s)
- Taeyoon Son
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Benquan Wang
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Damber Thapa
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Yiming Lu
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Yanjun Chen
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Dingcai Cao
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL 60612, 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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Zhao X, Thapa D, Wang B, Lu Y, Gai S, Yao X. Stimulus-evoked outer segment changes in rod photoreceptors. JOURNAL OF BIOMEDICAL OPTICS 2016; 21:65006. [PMID: 27334933 PMCID: PMC4917604 DOI: 10.1117/1.jbo.21.6.065006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 06/01/2016] [Indexed: 05/21/2023]
Abstract
Rod-dominated transient retinal phototropism (TRP) has been recently observed in freshly isolated mouse and frog retinas. Comparative confocal microscopy and optical coherence tomography revealed that the TRP was predominantly elicited from the rod outer segment (OS). However, the biophysical mechanism of rod OS dynamics is still unknown. Mouse and frog retinal slices, which displayed a cross-section of retinal photoreceptors and other functional layers, were used to test the effect of light stimulation on rod OSs. Time-lapse microscopy revealed stimulus-evoked conformational changes of rod OSs. In the center of the stimulated region, the length of the rod OS shrunk, while in the peripheral region, the rod OS swung toward the center region. Our experimental observation and theoretical analysis suggest that the TRP may reflect unbalanced rod disc-shape changes due to localized visible light stimulation.
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Affiliation(s)
- Xiaohui Zhao
- Hebei University, College of Physics Science and Technology, Hebei Key Lab of Optic-Electronic Information Materials, Baoding 071002, China
- University of Illinois at Chicago, Department of Bioengineering, Chicago, Illinois 60607, United States
| | - Damber Thapa
- University of Illinois at Chicago, Department of Bioengineering, Chicago, Illinois 60607, United States
| | - Benquan Wang
- University of Illinois at Chicago, Department of Bioengineering, Chicago, Illinois 60607, United States
| | - Yiming Lu
- University of Illinois at Chicago, Department of Bioengineering, Chicago, Illinois 60607, United States
| | - Shaoyan Gai
- University of Illinois at Chicago, Department of Bioengineering, Chicago, Illinois 60607, United States
| | - Xincheng Yao
- Hebei University, College of Physics Science and Technology, Hebei Key Lab of Optic-Electronic Information Materials, Baoding 071002, China
- University of Illinois at Chicago, Department of Bioengineering, Chicago, Illinois 60607, United States
- University of Illinois at Chicago, Department of Ophthalmology and Visual Sciences, Chicago, Illinois 60612, United States
- Address all correspondence to: Xincheng Yao, E-mail:
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Lindgren J, Moyer A, Schweitzer MH, Sjövall P, Uvdal P, Nilsson DE, Heimdal J, Engdahl A, Gren JA, Schultz BP, Kear BP. Interpreting melanin-based coloration through deep time: a critical review. Proc Biol Sci 2016; 282:20150614. [PMID: 26290071 DOI: 10.1098/rspb.2015.0614] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Colour, derived primarily from melanin and/or carotenoid pigments, is integral to many aspects of behaviour in living vertebrates, including social signalling, sexual display and crypsis. Thus, identifying biochromes in extinct animals can shed light on the acquisition and evolution of these biological traits. Both eumelanin and melanin-containing cellular organelles (melanosomes) are preserved in fossils, but recognizing traces of ancient melanin-based coloration is fraught with interpretative ambiguity, especially when observations are based on morphological evidence alone. Assigning microbodies (or, more often reported, their 'mouldic impressions') as melanosome traces without adequately excluding a bacterial origin is also problematic because microbes are pervasive and intimately involved in organismal degradation. Additionally, some forms synthesize melanin. In this review, we survey both vertebrate and microbial melanization, and explore the conflicts influencing assessment of microbodies preserved in association with ancient animal soft tissues. We discuss the types of data used to interpret fossil melanosomes and evaluate whether these are sufficient for definitive diagnosis. Finally, we outline an integrated morphological and geochemical approach for detecting endogenous pigment remains and associated microstructures in multimillion-year-old fossils.
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Affiliation(s)
- Johan Lindgren
- Department of Geology, Lund University, 223 62 Lund, Sweden
| | - Alison Moyer
- Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695, USA
| | - Mary H Schweitzer
- Department of Geology, Lund University, 223 62 Lund, Sweden Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695, USA North Carolina Museum of Natural Sciences, Raleigh, NC 27601, USA
| | - Peter Sjövall
- SP Technical Research Institute of Sweden, Chemistry, Materials and Surfaces, 501 15 Borås, Sweden
| | - Per Uvdal
- MAX-IV laboratory, Lund University, 221 00 Lund, Sweden Chemical Physics, Department of Chemistry, Lund University, 221 00 Lund, Sweden
| | - Dan E Nilsson
- Department of Biology, Lund University, 223 62 Lund, Sweden
| | - Jimmy Heimdal
- MAX-IV laboratory, Lund University, 221 00 Lund, Sweden
| | | | - Johan A Gren
- Department of Geology, Lund University, 223 62 Lund, Sweden
| | | | - Benjamin P Kear
- Museum of Evolution, Uppsala University, 752 36 Uppsala, Sweden Palaeobiology Programme, Department of Earth Sciences, Uppsala University, 752 36 Uppsala, Sweden
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Sevilla MB, McGwin G, Lad EM, Clark M, Yuan EL, Farsiu S, Curcio CA, Owsley C, Toth CA. Relating Retinal Morphology and Function in Aging and Early to Intermediate Age-related Macular Degeneration Subjects. Am J Ophthalmol 2016; 165:65-77. [PMID: 26940163 DOI: 10.1016/j.ajo.2016.02.021] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Revised: 02/17/2016] [Accepted: 02/19/2016] [Indexed: 11/15/2022]
Abstract
PURPOSE To evaluate relationships between age-related macular degeneration (AMD) morphology on spectral-domain optical coherence tomography (SDOCT) and visual function. DESIGN Cross-sectional, observational. METHODS From the Alabama Study on Early AMD baseline visit, visual acuity, cone-mediated sensitivity, rod-mediated dark adaptation, and SDOCT were obtained in 1 eye per subject with no apparent retinal aging (n = 15), normal aging (n = 15), early AMD (n = 15), and intermediate AMD (n = 46). The volumes of retinal pigment epithelium (RPE)-drusen complex, RPE-drusen complex abnormal thinning, RPE-drusen complex abnormal thickening, and inner and outer retina were calculated in specified regions using semi-automated SDOCT segmentation. RESULTS Better cone-mediated sensitivity was associated with greater RPE-drusen complex volume (r = 0.34, P < .001) and less RPE-drusen complex abnormal thinning volume (r = -0.31, P = .003). Longer rod-mediated dark adaptation time, the duration for rod-mediated sensitivity to recover from photo-bleach exposure, correlated with lower RPE-drusen complex volume (r = -0.34, P = .005) and greater RPE-drusen complex abnormal thinning volume (r = 0.280, P = .023). In 19 eyes with subretinal drusenoid deposits (SDD) vs 47 eyes without SDD, rod-mediated dark adaptation time was longer (mean ± SD 13.5 ± 7.0 vs 10.2 ± 3.1 minutes, P = .004), RPE-drusen complex abnormal thinning volume was greater (P < .0001), and visual acuity and cone sensitivity did not differ. CONCLUSION Decreased function relates to structural markers on SDOCT in AMD. Because the RPE-drusen complex includes the interdigitation of outer segments and RPE apical processes and SDD in eyes with AMD, slower dark adaptation might be related to structural abnormalities of the RPE, the RPE-photoreceptor interface, or both.
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Affiliation(s)
- Monica B Sevilla
- Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina
| | - Gerald McGwin
- Department of Ophthalmology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama; Department of Epidemiology, School of Public Health, University of Alabama at Birmingham, Birmingham, Alabama
| | - Eleonora M Lad
- Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina
| | - Mark Clark
- Department of Ophthalmology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - Eric L Yuan
- Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina
| | - Sina Farsiu
- Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina; Department of Biomedical Engineering, Pratt School of Engineering, Duke University, Durham, North Carolina
| | - Christine A Curcio
- Department of Ophthalmology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - Cynthia Owsley
- Department of Ophthalmology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - Cynthia A Toth
- Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina; Department of Biomedical Engineering, Pratt School of Engineering, Duke University, Durham, North Carolina.
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Chen B, Gao E, Chen H, Yang J, Shi F, Zheng C, Zhu W, Xiang D, Chen X, Zhang M. Profile and Determinants of Retinal Optical Intensity in Normal Eyes with Spectral Domain Optical Coherence Tomography. PLoS One 2016; 11:e0148183. [PMID: 26863010 PMCID: PMC4749251 DOI: 10.1371/journal.pone.0148183] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2015] [Accepted: 01/14/2016] [Indexed: 11/19/2022] Open
Abstract
Purpose To investigate the profile and determinants of retinal optical intensity in normal subjects using 3D spectral domain optical coherence tomography (SD OCT). Methods A total of 231 eyes from 231 healthy subjects ranging in age from 18 to 80 years were included and underwent a 3D OCT scan. Forty-four eyes were randomly chosen to be scanned by two operators for reproducibility analysis. Distribution of optical intensity of each layer and regions specified by the Early Treatment of Diabetic Retinopathy Study (ETDRS) were investigated by analyzing the OCT raw data with our automatic graph-based algorithm. Univariate and multivariate analyses were performed between retinal optical intensity and sex, age, height, weight, spherical equivalent (SE), axial length, image quality, disc area and rim/disc area ratio (R/D area ratio). Results For optical intensity measurements, the intraclass correlation coefficient of each layer ranged from 0.815 to 0.941, indicating good reproducibility. Optical intensity was lowest in the central area of retinal nerve fiber layer, ganglion cell layer, inner plexiform layer, inner nuclear layer, outer plexiform layer and photoreceptor layer, except for the retinal pigment epithelium (RPE). Optical intensity was positively correlated with image quality in all retinal layers (0.553<β<0.851, p<0.01), and negatively correlated with age in most retinal layers (-0.362<β<-0.179, p<0.01), except for the RPE (β = 0.456, p<0.01), outer nuclear layer and photoreceptor layer (p>0.05). There was no relationship between retinal optical intensity and sex, height, weight, SE, axial length, disc area and R/D area ratio. Conclusions There was a specific pattern of distribution of retinal optical intensity in different regions. The optical intensity was affected by image quality and age. Image quality can be used as a reference for normalization. The effect of age needs to be taken into consideration when using OCT for diagnosis.
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Affiliation(s)
- Binyao Chen
- Joint Shantou International Eye Center, Shantou University and the Chinese University of Hong Kong, Shantou, China
| | - Enting Gao
- School of Electronics and Information Engineering, Soochow University, Suzhou, China
| | - Haoyu Chen
- Joint Shantou International Eye Center, Shantou University and the Chinese University of Hong Kong, Shantou, China
| | - Jianling Yang
- Joint Shantou International Eye Center, Shantou University and the Chinese University of Hong Kong, Shantou, China
| | - Fei Shi
- School of Electronics and Information Engineering, Soochow University, Suzhou, China
| | - Ce Zheng
- Joint Shantou International Eye Center, Shantou University and the Chinese University of Hong Kong, Shantou, China
| | - Weifang Zhu
- School of Electronics and Information Engineering, Soochow University, Suzhou, China
| | - Dehui Xiang
- School of Electronics and Information Engineering, Soochow University, Suzhou, China
| | - Xinjian Chen
- School of Electronics and Information Engineering, Soochow University, Suzhou, China
- * E-mail: (MZ); (XC)
| | - Mingzhi Zhang
- Joint Shantou International Eye Center, Shantou University and the Chinese University of Hong Kong, Shantou, China
- * E-mail: (MZ); (XC)
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What biomarkers explain about pterygium OCT pattern. Graefes Arch Clin Exp Ophthalmol 2015; 254:143-8. [DOI: 10.1007/s00417-015-3186-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Revised: 09/17/2015] [Accepted: 09/30/2015] [Indexed: 11/24/2022] Open
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Li L, Dai C, Li Q, Zhao Q, Jiang X, Chai X, Zhou C. Fast subcellular optical coherence photoacoustic microscopy for pigment cell imaging. OPTICS LETTERS 2015; 40:4448-4451. [PMID: 26421553 DOI: 10.1364/ol.40.004448] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We developed a fast ultrahigh resolution optical coherence photoacoustic microscopy (FU-OCPAM) system by combining two complementary imaging modes of optical coherence microscopy (OCM) and photoacoustic microscopy (PAM) for cellular/subcellular imaging. The system used optical scanning to realize fast imaging speed and provided ultrahigh resolution of 1.24 and 0.59 μm for OCM and PAM, respectively. We imaged the retinal pigment epithelium (RPE) to demonstrate the subcellular imaging capability of the FU-OCPAM system. The OCM and PAM images clearly showed the RPE cell morphology and reflected the complementary optical properties of scattering and absorption. A quantitative analysis of the RPE cells was made based on photoacoustic (PA) signals. The cell area mainly ranged from 80 to 300 μm2, and had a linear relationship with the sum intensity of PA signals which mainly reflected the melanin content of the cells. The morphology and the PA signal could be used to identify qualitatively and quantitatively the aging and healthy states of the RPE cells. The results show the potential applications in studying the real-time cellular response to external stimulations and the progress of aging and diseases at the cellular level with FU-OCPAM.
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Zanzottera EC, Messinger JD, Ach T, Smith RT, Freund KB, Curcio CA. The Project MACULA Retinal Pigment Epithelium Grading System for Histology and Optical Coherence Tomography in Age-Related Macular Degeneration. Invest Ophthalmol Vis Sci 2015; 56:3253-68. [PMID: 25813989 DOI: 10.1167/iovs.15-16431] [Citation(s) in RCA: 113] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
PURPOSE To seek pathways of retinal pigment epithelium (RPE) fate in age-related macular degeneration via a morphology grading system; provide nomenclature, visualization targets, and metrics for clinical imaging and model systems. METHODS Donor eyes with geographic atrophy (GA) or choroidal neovascularization (CNV) and one GA eye with previous clinical spectral-domain optical coherence tomography (SDOCT) imaging were processed for histology, photodocumented, and annotated at predefined locations. Retinal pigment epithelial cells contained spindle-shaped melanosomes, apposed a basal lamina or basal laminar deposit (BLamD), and exhibited recognizable morphologies. Thicknesses and unbiased estimates of frequencies were obtained. RESULTS In 13 GA eyes (449 locations), 'Shedding,' 'Sloughed,' and 'Dissociated' morphologies were abundant; 22.2% of atrophic locations had 'Dissociated' RPE. In 39 CNV eyes (1363 locations), 37.3% of locations with fibrovascular/fibrocellular scar had 'Entombed' RPE; 'Sloughed,' 'Dissociated,' and 'Bilaminar' morphologies were abundant. Of abnormal RPE, CNV and GA both had ~35% 'Sloughed'/'Intraretinal,' with more Intraretinal in CNV (9.5% vs. 1.8%). 'Shedding' cells associated with granule aggregations in BLamD. The RPE layer did not thin, and BLamD remained thick, with progression. Granule-containing material consistent with three morphologies correlated to SDOCT hyperreflective foci in the previously examined GA patient. CONCLUSIONS Retinal pigment epithelium morphology indicates multiple pathways in GA and CNV. Atrophic/scarred areas have numerous cells capable of transcribing genes and generating imaging signals. Shed granule aggregates, possibly apoptotic, are visible in SDOCT, as are 'Dissociated' and 'Sloughed' cells. The significance of RPE phenotypes is addressable in longitudinal, high-resolution imaging in clinic populations. Data can motivate future molecular phenotyping studies.
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Affiliation(s)
- Emma C Zanzottera
- Department of Ophthalmology University of Alabama School of Medicine, Birmingham, Alabama, United States 2Eye Clinic, Department of Clinical Science "Luigi Sacco," Sacco Hospital, University of Milan, Milan, Italy
| | - Jeffrey D Messinger
- Department of Ophthalmology University of Alabama School of Medicine, Birmingham, Alabama, United States
| | - Thomas Ach
- Department of Ophthalmology University of Alabama School of Medicine, Birmingham, Alabama, United States 3University Hospital Würzburg, Department of Ophthalmology, Würzburg, Germany
| | - R Theodore Smith
- Department of Ophthalmology, New York University School of Medicine, New York City, New York, United States
| | - K Bailey Freund
- Department of Ophthalmology, New York University School of Medicine, New York City, New York, United States 5Vitreous Retina Macula Consultants of New York, New York, New York, United States 6LuEsther T. Mertz Retinal Research Center, Manhattan Eye, Ear
| | - Christine A Curcio
- Department of Ophthalmology University of Alabama School of Medicine, Birmingham, Alabama, United States
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