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Zhang P, Vafaeva O, Dolf C, Ma Y, Wang G, Cho J, Chan HHL, Marsh-Armstrong N, Zawadzki RJ. Evaluating the performance of OCT in assessing static and potential dynamic properties of the retinal ganglion cells and nerve fiber bundles in the living mouse eye. BIOMEDICAL OPTICS EXPRESS 2023; 14:6422-6441. [PMID: 38420317 PMCID: PMC10898556 DOI: 10.1364/boe.504637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 11/08/2023] [Accepted: 11/11/2023] [Indexed: 03/02/2024]
Abstract
Glaucoma is a group of eye diseases characterized by the thinning of the retinal nerve fiber layer (RNFL), which is primarily caused by the progressive death of retinal ganglion cells (RGCs). Precise monitoring of these changes at a cellular resolution in living eyes is significant for glaucoma research. In this study, we aimed to assess the effectiveness of temporal speckle averaging optical coherence tomography (TSA-OCT) and dynamic OCT (dOCT) in examining the static and potential dynamic properties of RGCs and RNFL in living mouse eyes. We evaluated parameters such as RNFL thickness and possible dynamics, as well as compared the ganglion cell layer (GCL) soma density obtained from in vivo OCT, fluorescence scanning laser ophthalmoscopy (SLO), and ex vivo histology.
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Affiliation(s)
- Pengfei Zhang
- School of Optoelectronic Engineering and Instrumentation Science, Dalian University of Technology, Dalian, 116024, China
- UC Davis EyePod Small Animals Ocular Imaging Laboratory, University of California Davis, Davis, CA 95616, USA
| | - Olga Vafaeva
- Department of Ophthalmology & Vision Science, University of California Davis Eye Center, 4860 Y Street, Suite 2400, Sacramento, CA 95817, USA
| | - Christian Dolf
- Department of Ophthalmology & Vision Science, University of California Davis Eye Center, 4860 Y Street, Suite 2400, Sacramento, CA 95817, USA
| | - Yanhong Ma
- School of Optoelectronic Engineering and Instrumentation Science, Dalian University of Technology, Dalian, 116024, China
| | - Guozhen Wang
- School of Optoelectronic Engineering and Instrumentation Science, Dalian University of Technology, Dalian, 116024, China
| | - Jessicca Cho
- UC Davis EyePod Small Animals Ocular Imaging Laboratory, University of California Davis, Davis, CA 95616, USA
| | - Henry Ho-Lung Chan
- Laboratory of Experimental Optometry (Neuroscience), School of Optometry, The Hong Kong Polytechnic University, Hong Kong, China
- Research Centre for SHARP Vision (RCSV), The Hong Kong Polytechnic University, Hong Kong, China
| | - Nicholas Marsh-Armstrong
- Department of Ophthalmology & Vision Science, University of California Davis Eye Center, 4860 Y Street, Suite 2400, Sacramento, CA 95817, USA
| | - Robert J Zawadzki
- UC Davis EyePod Small Animals Ocular Imaging Laboratory, University of California Davis, Davis, CA 95616, USA
- Center for Human Ocular Imaging Research (CHOIR), Dept. of Ophthalmology & Vision Science, University of California Davis, 4860 Y Street, Suite 2400, Sacramento, CA 95817, USA
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2
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Gao S, Zeng Y, Li Y, Cohen ED, Berkowitz BA, Qian H. Fast and slow light-induced changes in murine outer retina optical coherence tomography: complementary high spatial resolution functional biomarkers. PNAS NEXUS 2022; 1:pgac208. [PMID: 36338188 PMCID: PMC9615127 DOI: 10.1093/pnasnexus/pgac208] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Accepted: 09/21/2022] [Indexed: 11/18/2022]
Abstract
Fast (seconds) and slow (minutes to hours) optical coherence tomography (OCT) responses to light stimulation have been developed to probe outer retinal function with higher spatial resolution than the classical full-field electroretinogram (ERG). However, the relationships between functional information revealed by OCT and ERG are largely unexplored. In this study, we directly compared the fast and slow OCT responses with the ERG. Fast responses [i.e. the optoretinogram (ORG)] are dominated by reflectance changes in the outer segment (OS) and the inner segment ellipsoid zone (ISez). The ORG OS response has faster kinetics and a higher light sensitivity than the ISez response, and both differ significantly with ERG parameters. Sildenafil-inhibition of phototransduction reduced the ORG light sensitivity, suggesting a complete phototransduction pathway is needed for ORG responses. Slower OCT responses were dominated by light-induced changes in the external limiting membrane to retinal pigment epithelium (ELM-RPE) thickness and photoreceptor-tip hyporeflective band (HB) magnitudes, with the biggest changes occurring after prolonged light stimulation. Mice with high (129S6/ev) vs. low (C57BL/6 J) ATP(adenosine triphosphate) synthesis efficiency show similar fast ORG, but dissimilar slow OCT responses. We propose that the ORG reflects passive physiology, such as water movement from photoreceptors, in response to the photocurrent response (measurable by ERG), whereas the slow OCT responses measure mitochondria-driven physiology in the outer retina, such as dark-provoked water removal from the subretinal space.
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Affiliation(s)
- Shasha Gao
- Department of Ophthalmology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450001, China
- Visual Function Core, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Yong Zeng
- 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
| | - 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 20993-0002, USA
| | - Bruce A Berkowitz
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University School of Medicine, Detroit, MI 48202, USA
| | - Haohua Qian
- Visual Function Core, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
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3
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Pfäffle C, Spahr H, Gercke K, Puyo L, Höhl S, Melenberg D, Miura Y, Hüttmann G, Hillmann D. Phase-Sensitive Measurements of Depth-Dependent Signal Transduction in the Inner Plexiform Layer. Front Med (Lausanne) 2022; 9:885187. [PMID: 35721092 PMCID: PMC9198552 DOI: 10.3389/fmed.2022.885187] [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: 02/27/2022] [Accepted: 05/10/2022] [Indexed: 12/01/2022] Open
Abstract
Non-invasive spatially resolved functional imaging in the human retina has recently attracted considerable attention. Particularly functional imaging of bipolar and ganglion cells could aid in studying neuronal activity in humans, including an investigation of processes of the central nervous system. Recently, we imaged the activity of the inner neuronal layers by measuring nanometer-size changes of the cells within the inner plexiform layer (IPL) using phase-sensitive optical coherence tomography (OCT). In the IPL, there are connections between the neuronal cells that are dedicated to the processing of different aspects of the visual information, such as edges in the image or temporal changes. Still, so far, it was not possible to assign functional changes to single cells or cell classes in living humans, which is essential for studying the vision process. One characteristic of signal processing in the IPL is that different aspects of the visual impression are only processed in specific sub-layers (strata). Here, we present an investigation of these functional signals for three different sub-layers in the IPL with the aim to separate different properties of the visual signal processing. Whereas the inner depth-layer, closest to the ganglion cells, exhibits an increase in the optical path length, the outer depth-layer, closest to the bipolar cell layer, exhibits a decrease in the optical path length. Additionally, we found that the central depth is sensitive to temporal changes, showing a maximum response at a stimulation frequency of around 12.5 Hz. The results demonstrate that the signals from different cell types can be distinguished by phase-sensitive OCT.
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Affiliation(s)
- Clara Pfäffle
- Institute of Biomedical Optic, University of Lübeck, Lübeck, Germany
| | - Hendrik Spahr
- Institute of Biomedical Optic, University of Lübeck, Lübeck, Germany
| | - Katharina Gercke
- Institute of Biomedical Optic, University of Lübeck, Lübeck, Germany
| | - Léo Puyo
- Institute of Biomedical Optic, University of Lübeck, Lübeck, Germany.,Medical Laser Center Lübeck GmbH, Lübeck, Germany
| | - Svea Höhl
- Institute of Biomedical Optic, University of Lübeck, Lübeck, Germany
| | - David Melenberg
- Institute of Biomedical Optic, University of Lübeck, Lübeck, Germany
| | - Yoko Miura
- Institute of Biomedical Optic, University of Lübeck, Lübeck, Germany.,Department of Ophthalmology, University of Lübeck, Lübeck, Germany
| | - Gereon Hüttmann
- Institute of Biomedical Optic, University of Lübeck, Lübeck, Germany.,Airway Research Center North, Member of the German Center for Lung Research, Grosshansdorf, Germany.,Center of Brain, Behavior and Metabolism (CBBM), University of Lübeck, Lübeck, Germany
| | - Dierck Hillmann
- Institute of Biomedical Optic, University of Lübeck, Lübeck, Germany.,Thorlabs GmbH, Lübeck, Germany.,Department of Physics, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
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4
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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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5
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Pijewska E, Zhang P, Meina M, Meleppat RK, Szkulmowski M, Zawadzki RJ. Extraction of phase-based optoretinograms (ORG) from serial B-scans acquired over tens of seconds by mouse retinal raster scanning OCT system. BIOMEDICAL OPTICS EXPRESS 2021; 12:7849-7871. [PMID: 35003871 PMCID: PMC8713677 DOI: 10.1364/boe.439900] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 11/01/2021] [Accepted: 11/08/2021] [Indexed: 06/14/2023]
Abstract
Several specialized retinal optical coherence tomography (OCT) acquisition and processing methods have been recently developed to allow in vivo probing of light-evoked photoreceptors function, focusing on measurements in individual photoreceptors (rods and cones). Recent OCT investigations in humans and experimental animals have shown that the outer segments in dark-adapted rods and cones elongate in response to the visible optical stimuli that bleach fractions of their visual photopigment. We have previously successfully contributed to these developments by implementing OCT intensity-based "optoretinograms" (ORG), the paradigm of using near-infrared OCT (NIR OCT) to measure bleaching-induced back-scattering and/or elongation changes of photoreceptors in the eye in vivo. In parallel, several groups have successfully implemented phase-based ORGs, mainly in human studies, exploiting changes in the phases of back-scattered light. This allowed more sensitive observations of tiny alterations of photoreceptors structures. Applications of the phase-based ORG have been implemented primarily in high speed and cellular resolution AO-OCT systems that can visualize photoreceptor mosaic, allowing phase measurements of path length changes in outer segments of individual photoreceptors. The phase-based ORG in standard resolution OCT systems is much more demanding to implement and has not been explored extensively. This manuscript describes our efforts to implement a phase analysis framework to retinal images acquired with a standard resolution and raster scanning OCT system, which offers much lower phase stability than line-field or full-field OCT detection schemes due to the relatively slower acquisition speed. Our initial results showcase the successful extraction of phase-based ORG signal from the B-scans acquired at ∼100 Hz rate and its favorable comparison with intensity-based ORG signal extracted from the same data sets. We implemented the calculation of phase-based ORG signals using Knox-Thompson paths and modified signal recovery by adding decorrelation weights. The phase-sensitive ORG signal analysis developed here for mouse retinal raster scanning OCT systems could be in principle extended to clinical retinal raster scanning OCT systems, potentially opening doors for clinically friendly ORG probing.
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Affiliation(s)
- Ewelina Pijewska
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University in Toruń, Grudziądzka 5, 87-100 Torun, Poland
| | - Pengfei Zhang
- UC Davis Eyepod Imaging Laboratory, Dept. of Cell Biology and Human Anatomy, University of California Davis, 4320 Tupper Hall, Davis, CA 95616, USA
- School of Optoelectronic Engineering and Instrumentation Science, Dalian University of Technology, No. 2 Linggong Road, Ganjingzi District, Dalian City, Liaoning Province 116024, China
| | - Michał Meina
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University in Toruń, Grudziądzka 5, 87-100 Torun, Poland
| | - Ratheesh K. Meleppat
- UC Davis Eyepod Imaging Laboratory, Dept. of Cell Biology and Human Anatomy, University of California Davis, 4320 Tupper Hall, Davis, CA 95616, USA
| | - Maciej Szkulmowski
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University in Toruń, Grudziądzka 5, 87-100 Torun, Poland
| | - Robert J. Zawadzki
- UC Davis Eyepod Imaging Laboratory, Dept. of Cell Biology and Human Anatomy, University of California Davis, 4320 Tupper Hall, Davis, CA 95616, USA
- Department of Ophthalmology & Vision Science, University of California Davis, 4860 Y Street Suite 2400 Sacramento, CA 95817, USA
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6
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Pfäffle C, Spahr H, Kutzner L, Burhan S, Hilge F, Miura Y, Hüttmann G, Hillmann D. Simultaneous functional imaging of neuronal and photoreceptor layers in living human retina. OPTICS LETTERS 2019; 44:5671-5674. [PMID: 31774751 DOI: 10.1364/ol.44.005671] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Accepted: 10/24/2019] [Indexed: 05/18/2023]
Abstract
Functional retinal imaging, especially of neuronal activity non-invasively in humans, is of tremendous interest. Although the activation of photoreceptor cells (PRCs) could be detected in humans, imaging the function of other retinal neurons had been so far hardly possible. Here, using phase-sensitive full-field swept-source optical coherence tomography (FF-SS-OCT), we show simultaneous imaging of the activation in the photoreceptor and ganglion cell layer/inner plexiform layer (GCL/IPL). The signals from the GCL/IPL are 10-fold smaller than those from the PRC and were detectable only using algorithms for suppression of motion artifacts and pulsatile blood flow in the retinal vessels. FF-SS-OCT with improved phase evaluation algorithms, therefore, allowed us to map functional connections between PRC and GCL/IPL, confirming previous ex vivo results. The demonstrated functional imaging of retinal neuronal layers can be a valuable tool in diagnostics and basic research.
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Abstract
Retinal function has long been studied with psychophysical methods in humans, whereas detailed functional studies of vision have been conducted mostly in animals owing to the invasive nature of physiological approaches. There are exceptions to this generalization, for example, the electroretinogram. This review examines exciting recent advances using in vivo retinal imaging to understand the function of retinal neurons. In some cases, the methods have existed for years and are still being optimized. In others, new methods such as optophysiology are revealing novel patterns of retinal function in animal models that have the potential to change our understanding of the functional capacity of the retina. Together, the advances in retinal imaging mark an important milestone that shifts attention away from anatomy alone and begins to probe the function of healthy and diseased eyes.
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Affiliation(s)
- Jennifer J Hunter
- Flaum Eye Institute and Center for Visual Science, University of Rochester, Rochester, New York 14604, USA; , ,
- The Institute of Optics and Department of Biomedical Engineering, University of Rochester, Rochester, New York 14604, USA
| | - William H Merigan
- Flaum Eye Institute and Center for Visual Science, University of Rochester, Rochester, New York 14604, USA; , ,
| | - Jesse B Schallek
- Flaum Eye Institute and Center for Visual Science, University of Rochester, Rochester, New York 14604, USA; , ,
- Department of Neuroscience, University of Rochester, Rochester, New York 14604, USA
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8
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Sajdak BS, Salmon AE, Cava JA, Allen KP, Freling S, Ramamirtham R, Norton TT, Roorda A, Carroll J. Noninvasive imaging of the tree shrew eye: Wavefront analysis and retinal imaging with correlative histology. Exp Eye Res 2019; 185:107683. [PMID: 31158381 DOI: 10.1016/j.exer.2019.05.023] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2019] [Revised: 05/21/2019] [Accepted: 05/28/2019] [Indexed: 02/08/2023]
Abstract
Tree shrews are small mammals with excellent vision and are closely related to primates. They have been used extensively as a model for studying refractive development, myopia, and central visual processing and are becoming an important model for vision research. Their cone dominant retina (∼95% cones) provides a potential avenue to create new damage/disease models of human macular pathology and to monitor progression or treatment response. To continue the development of the tree shrew as an animal model, we provide here the first measurements of higher order aberrations along with adaptive optics scanning light ophthalmoscopy (AOSLO) images of the photoreceptor mosaic in the tree shrew retina. To compare intra-animal in vivo and ex vivo cone density measurements, the AOSLO images were matched to whole-mount immunofluorescence microscopy. Analysis of the tree shrew wavefront indicated that the optics are well-matched to the sampling of the cone mosaic and is consistent with the suggestion that juvenile tree shrews are nearly emmetropic (slightly hyperopic). Compared with in vivo measurements, consistently higher cone density was measured ex vivo, likely due to tissue shrinkage during histological processing. Tree shrews also possess massive mitochondria ("megamitochondria") in their cone inner segments, providing a natural model to assess how mitochondrial size affects in vivo retinal imagery. Intra-animal in vivo and ex vivo axial distance measurements were made in the outer retina with optical coherence tomography (OCT) and transmission electron microscopy (TEM), respectively, to determine the origin of sub-cellular cone reflectivity seen on OCT. These results demonstrate that these megamitochondria create an additional hyper-reflective outer retinal reflective band in OCT images. The ability to use noninvasive retinal imaging in tree shrews supports development of this species as a model of cone disorders.
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Affiliation(s)
- Benjamin S Sajdak
- Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI, United States; Ophthalmology and Visual Sciences, Medical College of Wisconsin, Milwaukee, WI, United States; Morgridge Institute for Research, Madison, WI, United States
| | - Alexander E Salmon
- Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Jenna A Cava
- Ophthalmology and Visual Sciences, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Kenneth P Allen
- Biomedical Resource Center, Medical College of Wisconsin, Milwaukee, WI, United States; Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Susan Freling
- Max Planck Florida Institute for Neuroscience, Jupiter, FL, United States
| | - Ramkumar Ramamirtham
- Ophthalmology, Boston Children's Hospital, Boston, MA, United States; Harvard Medical School, Boston, MA, United States
| | - Thomas T Norton
- Optometry and Vision Science, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Austin Roorda
- School of Optometry and Vision Science Graduate Group, University of California Berkeley, Berkeley, CA, United States
| | - Joseph Carroll
- Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI, United States; Ophthalmology and Visual Sciences, Medical College of Wisconsin, Milwaukee, WI, United States.
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