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Chauhan P, Kho AM, Srinivasan VJ. From Soma to Synapse: Imaging Age-Related Rod Photoreceptor Changes in the Mouse with Visible Light OCT. OPHTHALMOLOGY SCIENCE 2023; 3:100321. [PMID: 37388138 PMCID: PMC10302163 DOI: 10.1016/j.xops.2023.100321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 04/05/2023] [Accepted: 04/24/2023] [Indexed: 07/01/2023]
Abstract
Purpose Although the outer nuclear layer (ONL) and outer plexiform layer (OPL) each exhibit a complex internal organization, near-infrared OCT depicts both as monolithic bands. Here, using visible light OCT in the C57BL/6J mouse retina, sublaminar age-related changes in photoreceptor features were imaged and interpreted. These features were (1) oscillations in reflectivity, or striations, in the ONL and (2) a moderately reflective subband in the OPL. Design Cross-sectional study. Participants Pigmented mice (C57BL/6J, n = 14). Methods A 1.0-μm axial resolution visible light spectral/Fourier domain OCT system was used for in vivo retinal imaging. Light and electron microscopy were performed ex vivo. Linear mixed effects models or regression were employed for statistical analysis. Main Outcome Measures Comparison of OCT subbands with corresponding histological features, as well as quantification of subband thickness and reflectivity. Results Corresponding histological comparisons confirm that striations in the ONL arise from the rowlike arrangement of photoreceptor nuclei and reveal that the moderately reflective OPL subband arises from rod spherules. Compression of outer ONL striations with age suggests changes in soma organization. Thinning of the moderately reflective OPL subband with age supports a reduction of synapses in the OPL. Critically, the ONL somas are tightly correlated with the purported spherule layer but not with the rest of the OPL. Conclusions Visible light OCT imaging of the mouse OPL resolves postsynaptic and synaptic differences. Visible light OCT can study rod photoreceptor changes from the soma to the synapse in the living mouse retina. Financial Disclosures Proprietary or commercial disclosure may be found after the references.
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Affiliation(s)
- Pooja Chauhan
- Department of Radiology, NYU Langone Health, New York, New York
| | - Aaron M. Kho
- Department of Biomedical Engineering, University of California Davis, Davis, California
| | - Vivek J. Srinivasan
- Department of Radiology, NYU Langone Health, New York, New York
- Department of Biomedical Engineering, University of California Davis, Davis, California
- Department of Ophthalmology, NYU Langone Health, New York, New York
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2
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Shiga Y, Nishida T, Jeoung JW, Di Polo A, Fortune B. Optical Coherence Tomography and Optical Coherence Tomography Angiography: Essential Tools for Detecting Glaucoma and Disease Progression. FRONTIERS IN OPHTHALMOLOGY 2023; 3:1217125. [PMID: 37982032 PMCID: PMC10655832 DOI: 10.3389/fopht.2023.1217125] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 07/03/2023] [Indexed: 11/21/2023]
Abstract
Early diagnosis and detection of disease progression are critical to successful therapeutic intervention in glaucoma, the leading cause of irreversible blindness worldwide. Optical coherence tomography (OCT) is a non-invasive imaging technique that allows objective quantification in vivo of key glaucomatous structural changes in the retina and the optic nerve head (ONH). Advances in OCT technology have increased the scan speed and enhanced image quality, contributing to early glaucoma diagnosis and monitoring, as well as the visualization of critically important structures deep within the ONH, such as the lamina cribrosa. OCT angiography (OCTA) is a dye-free technique for noninvasively assessing ocular microvasculature, including capillaries within each plexus serving the macula, peripapillary retina and ONH regions, as well as the deeper vessels of the choroid. This layer-specific assessment of the microvasculature has provided evidence that retinal and choroidal vascular impairments can occur during early stages of glaucoma, suggesting that OCTA-derived measurements could be used as biomarkers for enhancing detection of glaucoma and its progression, as well as to reveal novel insights about pathophysiology. Moreover, these innovations have demonstrated that damage to the macula, a critical region for the vision-related quality of life, can be observed in the early stages of glaucomatous eyes, leading to a paradigm shift in glaucoma monitoring. Other advances in software and hardware, such as artificial intelligence-based algorithms, adaptive optics, and visible-light OCT, may further benefit clinical management of glaucoma in the future. This article reviews the utility of OCT and OCTA for glaucoma diagnosis and disease progression detection, emphasizes the importance of detecting macula damage in glaucoma, and highlights the future perspective of OCT and OCTA. We conclude that the OCT and OCTA are essential glaucoma detection and monitoring tools, leading to clinical and economic benefits for patients and society.
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Affiliation(s)
- Yukihiro Shiga
- Neuroscience Division, Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montréal, Québec H2X 0A9, Canada
- Department of Neuroscience, Université de Montréal, Montréal, Québec H3C 3J7, Canada
| | - Takashi Nishida
- Hamilton Glaucoma Center, Shiley Eye Institute, Viterbi Family Department of Ophthalmology, University of California, San Diego, La Jolla, California 92093, USA
| | - Jin Wook Jeoung
- Department of Ophthalmology, Seoul National University Hospital, Seoul National University College of Medicine, Seoul 03080, Republic of Korea
| | - Adriana Di Polo
- Neuroscience Division, Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montréal, Québec H2X 0A9, Canada
- Department of Neuroscience, Université de Montréal, Montréal, Québec H3C 3J7, Canada
| | - Brad Fortune
- Discoveries in Sight Research Laboratories, Devers Eye Institute and Legacy Research Institute, Legacy Health, 1225 NE Second Avenue, Portland, Oregon 97232, USA
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3
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Yang R, Ma Y, Zhao M, Han W, Li Q, Chen Z, Wang A, Yun Set S, Yamashita S, Zhang Z. Flat visible spectrum by a genetic algorithm optimized photonic crystal fiber in the GHz comb spacing. OPTICS LETTERS 2023; 48:2829-2832. [PMID: 37262221 DOI: 10.1364/ol.489285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Accepted: 04/02/2023] [Indexed: 06/03/2023]
Abstract
Coherent and flat supercontinuum (SC) sources are demanded for applications of metrology, spectroscopy, and bio-imaging. However, the process of SC generation is usually very complicated. We demonstrated a convenient and efficient method based on a genetic algorithm (GA). According to an objective spectrum, this algorithm could reverse-design the geometry of a fiber or waveguide without knowing the specific non-linear processes involved. Using this method, we designed a dispersion-managed photonic crystal fiber (PCF) for SC generation at 1 GHz comb spacing. With an input pulse of ∼150 fs, 450 pJ at 1050 nm, a 3 dB fluctuation spectrum ranging from 510 nm to 850 nm is obtained, which is absolutely fit to the calibration of an astronomical spectrograph.
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4
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Lupidi M, Mangoni L, Centini C, Pompucci G, Lanzafame L, Danieli L, Fruttini D, Peiretti E, Chhablani J, Mariotti C. Quantitative and Qualitative Assessments of Retinal Structure with Variable A-Scan Rate Spectralis OCT: Insights into IPL Multilaminarity. J Clin Med 2023; 12:jcm12072637. [PMID: 37048720 PMCID: PMC10094756 DOI: 10.3390/jcm12072637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2023] [Revised: 03/20/2023] [Accepted: 03/29/2023] [Indexed: 04/05/2023] Open
Abstract
The aim of this study was to evaluate the qualitative and quantitative differences between 20 and 85 kHz A-scan rate optical coherence tomography (OCT) images acquired by spectral domain OCT. The study included 60 healthy subjects analyzed with horizontal linear scans with a variable A-scan rate (SHIFT technology, Heidelberg Engineering, Heidelberg, Germany). The retinal thickness measurement of each retinal layer was performed in three different positions (subfoveal, nasal, and temporal). The qualitative assessment was performed by two independent observers who rated every image with a score ranging from 1 (“sufficient”) to 3 (“excellent”) on the basis of three parameters: visualization of the vitreo-retinal interface, characterization of the retinal layers, and visualization of the sclero-choroidal interface. No statistically significant differences in terms of retinal layer thickness between the two A-scan rate scans were observed (p > 0.05). The coefficient of variation of the retinal thickness values was lower in the 20 kHz group (25.8% versus 30.1% with the 85 kHz). The 20 kHz images showed a higher quality index for both observers. An inner plexiform layer (IPL) multilaminarity was detected in 78.3% of patients from the 20 kHz group and in 40% of patients from the 85 kHz group (p < 0.05).
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Affiliation(s)
- Marco Lupidi
- Eye Clinic, Department of Experimental and Clinical Medicine, Polytechnic University of Marche, 60126 Ancona, Italy
- Fondazione per la Macula Onlus, Di.N.O.G.Mi., University Eye Clinic, 16132 Genova, Italy
| | - Lorenzo Mangoni
- Eye Clinic, Department of Experimental and Clinical Medicine, Polytechnic University of Marche, 60126 Ancona, Italy
| | - Chiara Centini
- Eye Clinic, Department of Experimental and Clinical Medicine, Polytechnic University of Marche, 60126 Ancona, Italy
| | - Gregorio Pompucci
- Eye Clinic, Department of Experimental and Clinical Medicine, Polytechnic University of Marche, 60126 Ancona, Italy
| | - Luca Lanzafame
- Eye Clinic, Department of Experimental and Clinical Medicine, Polytechnic University of Marche, 60126 Ancona, Italy
| | | | - Daniela Fruttini
- Department of Medicine and Surgery, University of Perugia, S. Maria della Misericordia Hospital, 06123 Perugia, Italy
| | - Enrico Peiretti
- Eye Clinic, Department of Surgical Sciences, University of Cagliari, 09124 Cagliari, Italy
| | - Jay Chhablani
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Cesare Mariotti
- Eye Clinic, Department of Experimental and Clinical Medicine, Polytechnic University of Marche, 60126 Ancona, Italy
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5
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Song W, Zhang S, Kim YM, Sadlak N, Fiorello MG, Desai M, Yi J. Visible Light Optical Coherence Tomography of Peripapillary Retinal Nerve Fiber Layer Reflectivity in Glaucoma. Transl Vis Sci Technol 2022; 11:28. [PMID: 36166221 PMCID: PMC9526364 DOI: 10.1167/tvst.11.9.28] [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: 03/23/2022] [Accepted: 08/19/2022] [Indexed: 01/01/2023] Open
Abstract
Purpose To evaluate the clinical utility of visible light optical coherence tomography (VIS-OCT) and to test whether VIS-OCT reflectivity and spectroscopy of peripapillary retinal nerve fiber layer (pRNFL) are correlated with severity of glaucoma, compared with standard-of-care OCT thickness measurements. Methods In total 54 eyes (20 normal, 17 suspect/preperimetric glaucoma [GS/PPG], 17 perimetric glaucoma [PG]) were successfully imaged with complete datasets. All the eyes were scanned by a custom-designed dual-channel device that simultaneously acquired VIS-OCT and near-infrared OCT (NIR-OCT) images. A 5 × 5 mm2 scan was taken of the pRNFL. The pRNFL reflectivity was calculated for both channels and the spectroscopic marker was quantified by pVN, defined as the ratio of VIS-OCT to NIR-OCT pRNFL reflectivity. The results were compared with ophthalmic examinations and Zeiss Cirrus OCT. Results VIS-OCT pRNFL reflectivity significantly, sequentially decreased from normal to GS/PPG to PG, as did NIR-OCT pRNFL reflectivity. The pVN had the same decreasing trend among three groups. Normal and GS/PPG eyes were significantly different in VIS-OCT pRNFL reflectivity (P = 0.002) and pVN (P < 0.001), but were not in NIR-OCT pRNFL reflectivity (P = 0.14), circumpapillary RNFL thickness (P = 0.17), or macular ganglion cell layer and inner plexiform layer thickness (P = 0.07) in a mixed linear regression model. Conclusions VIS-OCT pRNFL reflectivity and pVN better distinguished GS/PPG from normal eyes than Cirrus OCT thickness measurements. Translational Relevance VIS-OCT pRNFL reflectivity and pVN could be useful metrics in the early detection of glaucoma upon further longitudinal validation.
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Affiliation(s)
- Weiye Song
- Department of Medicine, Boston University School of Medicine, Boston Medical Center, Boston, MA, USA
| | - Sui Zhang
- Department of Epidemiology, School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - Yumi Mun Kim
- Department of Philosophy & Neuroscience, Boston University, Boston, USA
| | - Natalie Sadlak
- Department of Ophthalmology, Boston Medical Center, Boston, MA, USA
| | | | - Manishi Desai
- Department of Ophthalmology, Boston Medical Center, Boston, MA, USA
| | - Ji Yi
- Department of Medicine, Boston University School of Medicine, Boston Medical Center, Boston, MA, USA
- Department of Ophthalmology, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, USA
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6
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Srinivasan VJ, Kho AM, Chauhan P. Visible Light Optical Coherence Tomography Reveals the Relationship of the Myoid and Ellipsoid to Band 2 in Humans. Transl Vis Sci Technol 2022; 11:3. [PMID: 36053140 PMCID: PMC9440607 DOI: 10.1167/tvst.11.9.3] [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: 01/04/2023] Open
Abstract
Purpose We employ visible light optical coherence tomography (OCT) to investigate the relationship between the myoid, ellipsoid, and band 2 in the living human retina. Rather than refute existing theories, we aim to reveal new bands and better delineate the structures at hand. Methods An upgraded spectral/Fourier domain visible light OCT prototype, with 1.0-µm axial resolution, imaged 13 eyes of 13 young adult human subjects (23–40 years old) without a history of ocular pathology. The external limiting membrane (band 1) and band 2 edges were segmented. Reflectivity was examined along the inner segment (IS), defined as extending from band 1 to the band 2 center, and within band 2 itself. Results Images highlight a nearly continuously resolved extrafoveal internal limiting membrane, the peripheral single-cell thick ganglion cell layer, and the peripheral photoreceptor axonal fiber layer, a peripheral division of band 2 into bands 2a and 2b, and a reflectivity-based division of the IS into “m” and “e” zones. Discussion Topography and transverse intensity variations of the outermost band 2b suggest an association with rods. The “m” and “e” zone border is consistent with the myoid–ellipsoid boundary, even recapitulating the well-documented distribution of mitochondria throughout the IS at the foveal center. Theories of outer retinal reflectivity in OCT must adequately explain these observations. Translational Relevance Findings support that band 2 does partially overlap with the ellipsoid in transversally averaged OCT images due to photoreceptor IS length dispersion but argue that the inner ellipsoid must be inner to band 2, as suggested by prior quantitative measurements.
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Affiliation(s)
- Vivek J Srinivasan
- Department of Ophthalmology, NYU Langone Health, New York, NY, USA.,Department of Radiology, NYU Langone Health, New York, NY, USA.,Tech4Health Institute, NYU Langone Health, New York, NY, USA.,Department of Biomedical Engineering, University of California, Davis, CA, USA
| | - Aaron M Kho
- Department of Biomedical Engineering, University of California, Davis, CA, USA
| | - Pooja Chauhan
- Department of Radiology, NYU Langone Health, New York, NY, USA.,Tech4Health Institute, NYU Langone Health, New York, NY, USA
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7
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Rubinoff I, Miller DA, Kuranov R, Wang Y, Fang R, Volpe NJ, Zhang HF. High-Speed Balanced-Detection Visible-Light Optical Coherence Tomography in the Human Retina Using Subpixel Spectrometer Calibration. IEEE TRANSACTIONS ON MEDICAL IMAGING 2022; 41:1724-1734. [PMID: 35089857 PMCID: PMC9921460 DOI: 10.1109/tmi.2022.3147497] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Increases in speed and sensitivity enabled rapid clinical adoption of optical coherence tomography (OCT) in ophthalmology. Recently, visible-light OCT (vis-OCT) achieved ultrahigh axial resolution, improved tissue contrast, and provided new functional imaging capabilities, demonstrating the potential to improve clinical care further. However, limited speed and sensitivity caused by the high relative intensity noise (RIN) in supercontinuum lasers impeded the clinical adoption of vis-OCT. To overcome these limitations, we developed balanced-detection vis-OCT (BD-vis-OCT), which uses two calibrated spectrometers to cancel RIN and other noises. We analyzed the RIN to achieve robust subpixel calibration between the two spectrometers and showed that BD-vis-OCT reduced the A-line noise floor by up to 20.5 dB. Metrics comparing signal-to-noise-ratios showed similar image qualities across multiple reference arm powers, a hallmark of operation near the shot-noise limit. We imaged healthy human retinas at an A-line rate of 125 kHz and a field-of-view up to 10 mm ×4 mm. We found that BD-vis-OCT revealed retinal anatomical features previously obscured by the noise floor.
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8
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Alexopoulos P, Madu C, Wollstein G, Schuman JS. The Development and Clinical Application of Innovative Optical Ophthalmic Imaging Techniques. Front Med (Lausanne) 2022; 9:891369. [PMID: 35847772 PMCID: PMC9279625 DOI: 10.3389/fmed.2022.891369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Accepted: 05/23/2022] [Indexed: 11/22/2022] Open
Abstract
The field of ophthalmic imaging has grown substantially over the last years. Massive improvements in image processing and computer hardware have allowed the emergence of multiple imaging techniques of the eye that can transform patient care. The purpose of this review is to describe the most recent advances in eye imaging and explain how new technologies and imaging methods can be utilized in a clinical setting. The introduction of optical coherence tomography (OCT) was a revolution in eye imaging and has since become the standard of care for a plethora of conditions. Its most recent iterations, OCT angiography, and visible light OCT, as well as imaging modalities, such as fluorescent lifetime imaging ophthalmoscopy, would allow a more thorough evaluation of patients and provide additional information on disease processes. Toward that goal, the application of adaptive optics (AO) and full-field scanning to a variety of eye imaging techniques has further allowed the histologic study of single cells in the retina and anterior segment. Toward the goal of remote eye care and more accessible eye imaging, methods such as handheld OCT devices and imaging through smartphones, have emerged. Finally, incorporating artificial intelligence (AI) in eye images has the potential to become a new milestone for eye imaging while also contributing in social aspects of eye care.
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Affiliation(s)
- Palaiologos Alexopoulos
- Department of Ophthalmology, NYU Langone Health, NYU Grossman School of Medicine, New York, NY, United States
| | - Chisom Madu
- Department of Ophthalmology, NYU Langone Health, NYU Grossman School of Medicine, New York, NY, United States
| | - Gadi Wollstein
- Department of Ophthalmology, NYU Langone Health, NYU Grossman School of Medicine, New York, NY, United States
- Department of Biomedical Engineering, NYU Tandon School of Engineering, Brooklyn, NY, United States
- Center for Neural Science, College of Arts & Science, New York University, New York, NY, United States
| | - Joel S. Schuman
- Department of Ophthalmology, NYU Langone Health, NYU Grossman School of Medicine, New York, NY, United States
- Department of Biomedical Engineering, NYU Tandon School of Engineering, Brooklyn, NY, United States
- Center for Neural Science, College of Arts & Science, New York University, New York, NY, United States
- Department of Electrical and Computer Engineering, NYU Tandon School of Engineering, Brooklyn, NY, United States
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9
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Tsunoda K, Hanazono G. Detailed analyses of microstructure of photoreceptor layer at different severities of occult macular dystrophy by ultrahigh-resolution SD-OCT. Am J Ophthalmol Case Rep 2022; 26:101490. [PMID: 35321252 PMCID: PMC8935511 DOI: 10.1016/j.ajoc.2022.101490] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 03/05/2022] [Accepted: 03/13/2022] [Indexed: 12/01/2022] Open
Abstract
Purpose To analyze the microstructures of the photoreceptor layer in detail in eyes with occult macular dystrophy (OMD, Miyake's disease) by ultrahigh-resolution spectral-domain optical coherence tomography (UHR-SD-OCT). Observations Twenty-eight normal subjects and 5 patients with OMD of different severities were studied. Cross-sectional images through the fovea were recorded with a UHR-SD-OCT system with a depth resolution of <2.0 μm. In patients with OMD, the UHR-SD-OCT images revealed abnormal photoreceptor microstructures which were not detected in the conventional SD-OCT images. The UHR-SD-OCT images showed that the interdigitation zone (IZ) was not present and the outer segments were hyperreflective with hyperreflective dots (HRDs) aligned like string of pearls during the earlier stages. There was a disruption of the ellipsoid zone (EZ) which appeared as clusters of larger HRDs, and these HRDs became less apparent with increasing time. The outer segments became hyporeflective and rod IZ became apparent with longer duration of the disease process. Conclusions and Importance The UHR-SD-OCT images show detailed characteristics of the photoreceptor microstructures of different severities during the progression of OMD. These detailed observations will help in understanding the mechanisms involved in the retinal pathology and should provide important information for their treatments.
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Affiliation(s)
- Kazushige Tsunoda
- Division of Vision Research, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, 2-5-1 Higashigaoka, Meguro-ku, Tokyo, 152-8902, Japan
- Corresponding author.
| | - Gen Hanazono
- Division of Vision Research, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, 2-5-1 Higashigaoka, Meguro-ku, Tokyo, 152-8902, Japan
- Higashimatsudo Hanazono Eye Clinic, 2-3-2 Higashimatsudo, Matsudo City, Chiba, 270-2225, Japan
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10
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Ghassabi Z, Kuranov RV, Schuman JS, Zambrano R, Wu M, Liu M, Tayebi B, Wang Y, Rubinoff I, Liu X, Wollstein G, Zhang HF, Ishikawa H. In Vivo Sublayer Analysis of Human Retinal Inner Plexiform Layer Obtained by Visible-Light Optical Coherence Tomography. Invest Ophthalmol Vis Sci 2022; 63:18. [PMID: 35024761 PMCID: PMC8762683 DOI: 10.1167/iovs.63.1.18] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Purpose Growing evidence suggests that dendrite retraction or degeneration in a subpopulation of the retinal ganglion cells (RGCs) may precede detectable soma abnormalities and RGC death in glaucoma. Visualization of the lamellar structure of the inner plexiform layer (IPL) could advance clinical management and fundamental understanding of glaucoma. We investigated whether visible-light optical coherence tomography (vis-OCT) could detect the difference in the IPL sublayer thicknesses between small cohorts of healthy and glaucomatous subjects. Method We imaged nine healthy and five glaucomatous subjects with vis-OCT. Four of the healthy subjects were scanned three times each in two separate visits, and five healthy and five glaucoma subjects were scanned three times during a single visit. IPL sublayers were manually segmented using averaged A-line profiles. Results The mean ages of glaucoma and healthy subjects are 59.6 ± 13.4 and 45.4 ± 14.4 years (P = 0.02.) The visual field mean deviations (MDs) are −26.4 to −7.7 dB in glaucoma patients and −1.6 to 1.1 dB in healthy subjects (P = 0.002). Median coefficients of variation (CVs) of intrasession repeatability for the entire IPL and three sublayers are 3.1%, 5.6%, 6.9%, and 5.6% in healthy subjects and 1.8%, 6.0%, 7.7%, and 6.2% in glaucoma patients, respectively. The mean IPL thicknesses are 36.2 ± 1.5 µm in glaucomatous and 40.1 ± 1.7 µm in healthy eyes (P = 0.003). Conclusions IPL sublayer analysis revealed that the middle sublayer could be responsible for the majority of IPL thinning in glaucoma. Vis-OCT quantified IPL sublayers with good repeatability in both glaucoma and healthy subjects.
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Affiliation(s)
- Zeinab Ghassabi
- Department of Ophthalmology, NYU Langone Health, NYU Grossman School of Medicine, New York, New York, United States
| | - Roman V Kuranov
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois, United States.,Opticent Inc., Evanston, Illinois, United States
| | - Joel S Schuman
- Department of Ophthalmology, NYU Langone Health, NYU Grossman School of Medicine, New York, New York, United States.,Department of Biomedical Engineering, New York University Tandon School of Engineering, Brooklyn, New York, United States.,Neuroscience Institute, NYU Langone Health, NYU Grossman School of Medicine, New York, New York, United States.,Department of Electrical and Computer Engineering, New York University Tandon School of Engineering, Brooklyn, New York, United States.,Center for Neural Science, NYU College of Arts and Sciences, New York, New York, United States.,Department of Physiology and Neuroscience, NYU Langone Health, NYU Grossman School of Medicine, New York, New York, United States
| | - Ronald Zambrano
- Department of Ophthalmology, NYU Langone Health, NYU Grossman School of Medicine, New York, New York, United States
| | - Mengfei Wu
- Department of Ophthalmology, NYU Langone Health, NYU Grossman School of Medicine, New York, New York, United States
| | - Mengling Liu
- Department of Ophthalmology, NYU Langone Health, NYU Grossman School of Medicine, New York, New York, United States
| | - Behnam Tayebi
- Department of Ophthalmology, NYU Langone Health, NYU Grossman School of Medicine, New York, New York, United States.,Neuroscience Institute, NYU Langone Health, NYU Grossman School of Medicine, New York, New York, United States
| | - Yuanbo Wang
- Opticent Inc., Evanston, Illinois, United States
| | - Ian Rubinoff
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois, United States
| | - Xiaorong Liu
- Department of Biology, University of Virginia, Charlottesville, Virginia, United States
| | - Gadi Wollstein
- Department of Ophthalmology, NYU Langone Health, NYU Grossman School of Medicine, New York, New York, United States.,Department of Biomedical Engineering, New York University Tandon School of Engineering, Brooklyn, New York, United States
| | - Hao F Zhang
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois, United States
| | - Hiroshi Ishikawa
- Department of Ophthalmology, NYU Langone Health, NYU Grossman School of Medicine, New York, New York, United States.,Department of Biomedical Engineering, New York University Tandon School of Engineering, Brooklyn, New York, United States.,Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States
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11
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Chen L, Cao D, Messinger JD, Ach T, Ferrara D, Freund KB, Curcio CA. Histology and clinical imaging lifecycle of black pigment in fibrosis secondary to neovascular age-related macular degeneration. Exp Eye Res 2022; 214:108882. [PMID: 34890604 PMCID: PMC8809488 DOI: 10.1016/j.exer.2021.108882] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 11/23/2021] [Accepted: 11/30/2021] [Indexed: 01/03/2023]
Abstract
PURPOSE Melanotic cells with large spherical melanosomes, thought to originate from retinal pigment epithelium (RPE), are found in eyes with neovascular age-related macular degeneration (nvAMD). To generate hypotheses about RPE participation in fibrosis, we correlate histology to clinical imaging in an eye with prominent black pigment in fibrotic scar secondary to nvAMD. METHODS Macular findings in a white woman with untreated inactive subretinal fibrosis due to nvAMD in her right eye were documented over 9 years with color fundus photography (CFP), fundus autofluorescence (FAF) imaging, and optical coherence tomography (OCT). After death (age 90 years), this index eye was prepared for light and electron microscopy to analyze 7 discrete zones of pigmentation in the fibrotic scar. In additional donor eyes with nvAMD, we determined the frequency of black pigment (n = 36 eyes) and immuno-labeled for retinoid, immunologic, and microglial markers (RPE65, CD68, Iba1, TMEM119; n = 3 eyes). RESULTS During follow-up of the index eye, black pigment appeared and expanded within a hypoautofluorescent fibrotic scar. The blackest areas correlated to melanotic cells (containing large spherical melanosomes), some in multiple layers. Pale areas had sparse pigmented cells. Gray areas correlated to cells with RPE organelles entombed in the scar and multinucleate cells containing sparse large spherical melanosomes. In 94% of nvAMD donor eyes, hyperpigmentation was visible. Certain melanotic cells expressed some RPE65 and mostly CD68. Iba1 and TMEM119 immunoreactivity, found both in retina and scar, did not co-localize with melanotic cells. CONCLUSION Hyperpigmentation in CFP results from both organelle content and optical superimposition effects. Black fundus pigment in nvAMD is common and corresponds to cells containing numerous large spherical melanosomes and superimposition of cells containing sparse large melanosomes, respectively. Melanotic cells are molecularly distinct from RPE, consistent with a process of transdifferentiation. The subcellular source of spherical melanosomes remains to be determined. Detailed histology of nvAMD eyes will inform future studies using technologies for spatially resolved molecular discovery to generate new therapies for fibrosis. The potential of black pigment as a biomarker for fibrosis can be investigated in clinical multimodal imaging datasets.
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Affiliation(s)
- Ling Chen
- The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Ophthalmology, Chongqing Eye Institute, Chongqing Branch of National Clinical Research Center for Ocular Diseases, Chongqing, PR China,Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham School of Medicine, Birmingham, AL, USA
| | - Dongfeng Cao
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham School of Medicine, Birmingham, AL, USA
| | - Jeffrey D. Messinger
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham School of Medicine, Birmingham, AL, USA
| | - Thomas Ach
- Department of Ophthalmology, University Hospital Bonn, Bonn, Germany
| | | | - K. Bailey Freund
- Vitreous Retina Macula Consultants of New York, New York, NY, USA,Department of Ophthalmology, New York University Grossman School of Medicine, New York, NY, USA
| | - Christine A. Curcio
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham School of Medicine, Birmingham, AL, USA,Corresponding author. Department of Ophthalmology and Visual Sciences; EyeSight Foundation of Alabama Vision Research Laboratories, 1670 University Boulevard Room 360; University of Alabama School of Medicine, Birmingham, AL, 35294-0099, USA. (C.A. Curcio)
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12
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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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13
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Beckmann L, Cai Z, Cole J, Miller DA, Liu M, Grannonico M, Zhang X, Ryu HJ, Netland PA, Liu X, Zhang HF. In vivo imaging of the inner retinal layer structure in mice after eye-opening using visible-light optical coherence tomography. Exp Eye Res 2021; 211:108756. [PMID: 34492282 PMCID: PMC10061273 DOI: 10.1016/j.exer.2021.108756] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 08/10/2021] [Accepted: 08/30/2021] [Indexed: 11/28/2022]
Abstract
The growth of the mouse eye and retina after birth is a dynamic, highly regulated process. In this study, we applied visible-light optical coherence tomography (vis-OCT), a non-invasive imaging technique, to examine developing retinal layer structures after eye-opening. We introduced a resampled circumpapillary B-scan averaging technique to improve the inter-layer contrast, enabling retinal layer thickness measurements as early as postnatal day 13 (P13) - right after eye-opening. We confirmed vis-OCT measurements using ex vivo confocal microscopy of retinal sections at different ages. Our results demonstrate that vis-OCT can visualize the developmental murine retinal layer structure in vivo, which offers us new opportunities to better characterize the pathological alterations in mouse models of developmental eye diseases.
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Affiliation(s)
- Lisa Beckmann
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA
| | - Zhen Cai
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA
| | - James Cole
- Department of Biology, University of Virginia, Charlottesville, VA, USA
| | - David A Miller
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA
| | - Mingna Liu
- Department of Biology, University of Virginia, Charlottesville, VA, USA
| | - Marta Grannonico
- Department of Biology, University of Virginia, Charlottesville, VA, USA
| | - Xian Zhang
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA
| | - Hyun Jung Ryu
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA
| | - Peter A Netland
- Department of Ophthalmology, University of Virginia, Charlottesville, VA, USA
| | - Xiaorong Liu
- Department of Biology, University of Virginia, Charlottesville, VA, USA; Department of Ophthalmology, University of Virginia, Charlottesville, VA, USA; Department of Psychology, University of Virginia, Charlottesville, VA, USA.
| | - Hao F Zhang
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA.
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14
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Leitgeb R, Placzek F, Rank E, Krainz L, Haindl R, Li Q, Liu M, Andreana M, Unterhuber A, Schmoll T, Drexler W. Enhanced medical diagnosis for dOCTors: a perspective of optical coherence tomography. JOURNAL OF BIOMEDICAL OPTICS 2021; 26:JBO-210150-PER. [PMID: 34672145 PMCID: PMC8528212 DOI: 10.1117/1.jbo.26.10.100601] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 09/23/2021] [Indexed: 05/17/2023]
Abstract
SIGNIFICANCE After three decades, more than 75,000 publications, tens of companies being involved in its commercialization, and a global market perspective of about USD 1.5 billion in 2023, optical coherence tomography (OCT) has become one of the fastest successfully translated imaging techniques with substantial clinical and economic impacts and acceptance. AIM Our perspective focuses on disruptive forward-looking innovations and key technologies to further boost OCT performance and therefore enable significantly enhanced medical diagnosis. APPROACH A comprehensive review of state-of-the-art accomplishments in OCT has been performed. RESULTS The most disruptive future OCT innovations include imaging resolution and speed (single-beam raster scanning versus parallelization) improvement, new implementations for dual modality or even multimodality systems, and using endogenous or exogenous contrast in these hybrid OCT systems targeting molecular and metabolic imaging. Aside from OCT angiography, no other functional or contrast enhancing OCT extension has accomplished comparable clinical and commercial impacts. Some more recently developed extensions, e.g., optical coherence elastography, dynamic contrast OCT, optoretinography, and artificial intelligence enhanced OCT are also considered with high potential for the future. In addition, OCT miniaturization for portable, compact, handheld, and/or cost-effective capsule-based OCT applications, home-OCT, and self-OCT systems based on micro-optic assemblies or photonic integrated circuits will revolutionize new applications and availability in the near future. Finally, clinical translation of OCT including medical device regulatory challenges will continue to be absolutely essential. CONCLUSIONS With its exquisite non-invasive, micrometer resolution depth sectioning capability, OCT has especially revolutionized ophthalmic diagnosis and hence is the fastest adopted imaging technology in the history of ophthalmology. Nonetheless, OCT has not been completely exploited and has substantial growth potential-in academics as well as in industry. This applies not only to the ophthalmic application field, but also especially to the original motivation of OCT to enable optical biopsy, i.e., the in situ imaging of tissue microstructure with a resolution approaching that of histology but without the need for tissue excision.
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Affiliation(s)
- Rainer Leitgeb
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
- Medical University of Vienna, Christian Doppler Laboratory OPTRAMED, Vienna, Austria
| | - Fabian Placzek
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
| | - Elisabet Rank
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
| | - Lisa Krainz
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
| | - Richard Haindl
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
| | - Qian Li
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
| | - Mengyang Liu
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
| | - Marco Andreana
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
| | - Angelika Unterhuber
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
| | - Tilman Schmoll
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
- Carl Zeiss Meditec, Inc., Dublin, California, United States
| | - Wolfgang Drexler
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
- Address all correspondence to Wolfgang Drexler,
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15
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Abstract
Early detection and monitoring are critical to the diagnosis and management of glaucoma, a progressive optic neuropathy that causes irreversible blindness. Optical coherence tomography (OCT) has become a commonly utilized imaging modality that aids in the detection and monitoring of structural glaucomatous damage. Since its inception in 1991, OCT has progressed through multiple iterations, from time-domain OCT, to spectral-domain OCT, to swept-source OCT, all of which have progressively improved the resolution and speed of scans. Even newer technological advancements and OCT applications, such as adaptive optics, visible-light OCT, and OCT-angiography, have enriched the use of OCT in the evaluation of glaucoma. This article reviews current commercial and state-of-the-art OCT technologies and analytic techniques in the context of their utility for glaucoma diagnosis and management, as well as promising future directions.
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Affiliation(s)
- Alexi Geevarghese
- Department of Ophthalmology, NYU Langone Health, NYU Grossman School of Medicine, New York, NY 10016, USA;
| | - Gadi Wollstein
- Department of Ophthalmology, NYU Langone Health, NYU Grossman School of Medicine, New York, NY 10016, USA;
- Department of Biomedical Engineering, NYU Tandon School of Engineering, Brooklyn, New York 11201, USA
- Center for Neural Science, NYU College of Arts and Sciences, New York, NY 10003, USA
| | - Hiroshi Ishikawa
- Department of Ophthalmology, NYU Langone Health, NYU Grossman School of Medicine, New York, NY 10016, USA;
- Department of Biomedical Engineering, NYU Tandon School of Engineering, Brooklyn, New York 11201, USA
| | - Joel S Schuman
- Department of Ophthalmology, NYU Langone Health, NYU Grossman School of Medicine, New York, NY 10016, USA;
- Department of Biomedical Engineering, NYU Tandon School of Engineering, Brooklyn, New York 11201, USA
- Center for Neural Science, NYU College of Arts and Sciences, New York, NY 10003, USA
- Department of Physiology and Neuroscience, NYU Langone Health, NYU Grossman School of Medicine, New York, NY 10016, USA
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16
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Wynne N, Carroll J, Duncan JL. Promises and pitfalls of evaluating photoreceptor-based retinal disease with adaptive optics scanning light ophthalmoscopy (AOSLO). Prog Retin Eye Res 2021; 83:100920. [PMID: 33161127 PMCID: PMC8639282 DOI: 10.1016/j.preteyeres.2020.100920] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 10/28/2020] [Accepted: 10/31/2020] [Indexed: 12/15/2022]
Abstract
Adaptive optics scanning light ophthalmoscopy (AOSLO) allows visualization of the living human retina with exquisite single-cell resolution. This technology has improved our understanding of normal retinal structure and revealed pathophysiological details of a number of retinal diseases. Despite the remarkable capabilities of AOSLO, it has not seen the widespread commercial adoption and mainstream clinical success of other modalities developed in a similar time frame. Nevertheless, continued advancements in AOSLO hardware and software have expanded use to a broader range of patients. Current devices enable imaging of a number of different retinal cell types, with recent improvements in stimulus and detection schemes enabling monitoring of retinal function, microscopic structural changes, and even subcellular activity. This has positioned AOSLO for use in clinical trials, primarily as exploratory outcome measures or biomarkers that can be used to monitor disease progression or therapeutic response. AOSLO metrics could facilitate patient selection for such trials, to refine inclusion criteria or to guide the choice of therapy, depending on the presence, absence, or functional viability of specific cell types. Here we explore the potential of AOSLO retinal imaging by reviewing clinical applications as well as some of the pitfalls and barriers to more widespread clinical adoption.
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Affiliation(s)
- Niamh Wynne
- Department of Ophthalmology and Visual Sciences, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Joseph Carroll
- Department of Ophthalmology and Visual Sciences, Medical College of Wisconsin, Milwaukee, WI, USA; Department of Cell Biology, Neurobiology & Anatomy, Medical College of Wisconsin, Milwaukee, WI, USA; Department of Biomedical Engineering, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Jacque L Duncan
- Department of Ophthalmology, University of California, San Francisco, CA, USA.
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17
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Abstract
Similar to other organs, the retina relies on tightly regulated perfusion and oxygenation. Previous studies have demonstrated that retinal blood flow is affected in a variety of eye and systemic diseases, including diabetic retinopathy, age-related macular degeneration, and glaucoma. Although measurement of peripheral oxygen saturation has become a standard clinical measurement through the development of pulse oximetry, developing a noninvasive technique to measure retinal oxygen saturation has proven challenging, and retinal oximetry technology currently remains inadequate for reliable clinical use. Here, we review current strategies and approaches, as well as several newer technologies in development, and discuss the future of retinal oximetry.
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Affiliation(s)
- Anupam K Garg
- Shiley Eye Institute, Viterbi Family Department of Ophthalmology, University of California San Diego, La Jolla, CA, USA.,School of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Darren Knight
- Shiley Eye Institute, Viterbi Family Department of Ophthalmology, University of California San Diego, La Jolla, CA, USA
| | - Leonardo Lando
- Shiley Eye Institute, Viterbi Family Department of Ophthalmology, University of California San Diego, La Jolla, CA, USA
| | - Daniel L Chao
- Shiley Eye Institute, Viterbi Family Department of Ophthalmology, University of California San Diego, La Jolla, CA, USA.,School of Medicine, University of California San Diego, La Jolla, CA, USA.,Janssen Research and Development, Raritan, NJ, USA
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18
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Zhang T, Kho AM, Srinivasan VJ. In vivo Morphometry of Inner Plexiform Layer (IPL) Stratification in the Human Retina With Visible Light Optical Coherence Tomography. Front Cell Neurosci 2021; 15:655096. [PMID: 33994948 PMCID: PMC8118202 DOI: 10.3389/fncel.2021.655096] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Accepted: 04/07/2021] [Indexed: 11/13/2022] Open
Abstract
From the bipolar cells to higher brain visual centers, signals in the vertebrate visual system are transmitted along parallel on and off pathways. These two pathways are spatially segregated along the depth axis of the retina. Yet, to our knowledge, there is no way to directly assess this anatomical stratification in vivo. Here, employing ultrahigh resolution visible light Optical Coherence Tomography (OCT) imaging in humans, we report a stereotyped reflectivity pattern of the inner plexiform layer (IPL) that parallels IPL stratification. We characterize the topography of this reflectivity pattern non-invasively in a cohort of normal, young adult human subjects. This proposed correlate of IPL stratification is accessible through non-invasive ocular imaging in living humans. Topographic variations should be carefully considered when designing studies in development or diseases of the visual system.
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Affiliation(s)
- Tingwei Zhang
- Department of Biomedical Engineering, University of California, Davis, Davis, CA, United States
| | - Aaron M. Kho
- Department of Biomedical Engineering, University of California, Davis, Davis, CA, United States
| | - Vivek J. Srinivasan
- Department of Biomedical Engineering, University of California, Davis, Davis, CA, United States
- Department of Ophthalmology and Vision Science, School of Medicine, University of California, Davis, Sacramento, CA, United States
- Department of Ophthalmology, NYU Langone Health, New York, NY, United States
- Department of Radiology, NYU Langone Health, New York, NY, United States
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19
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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] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 02/17/2021] [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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20
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Chen L, Messinger JD, Kar D, Duncan JL, Curcio CA. Biometrics, Impact, and Significance of Basal Linear Deposit and Subretinal Drusenoid Deposit in Age-Related Macular Degeneration. Invest Ophthalmol Vis Sci 2021; 62:33. [PMID: 33512402 PMCID: PMC7846955 DOI: 10.1167/iovs.62.1.33] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 01/04/2021] [Indexed: 02/07/2023] Open
Abstract
Purpose Basal linear deposit (BLinD) is a thin layer of soft drusen material. To elucidate the biology of extracellular deposits conferring age-related macular degeneration (AMD) progression risk and inform multimodal clinical imaging based on optical coherence tomography (OCT), we examined lipid content and regional prevalence of BLinD, soft drusen, pre-BLinD, and subretinal drusenoid deposit (SDD) in AMD and non-AMD aged eyes. We estimated BLinD volume and illustrated its relation to type 1 macular neovascularization (MNV). Methods Donor eyes were classified as early to intermediate AMD (n = 25) and age-matched controls (n = 54). In high-resolution histology, we assessed BLinD/soft drusen thickness at 836 and 1716 locations in AMD and control eyes, respectively. BLinD volume was estimated using solid geometry in donor eyes, one clinically characterized. Results BLinD, drusen, type 1 MNV, and fluid occupy the sub-RPE-basal laminar space. BLinD volume in a 3-mm diameter circle may be as much as 0.0315 mm3. Osmophilic lipid was more concentrated in BLinD/drusen than SDD. In the fovea, BLinD/drusen was prevalent in AMD eyes; pre-BLinD was prevalent in control eyes. SDD was low in the fovea and high in perifovea, especially in AMD eyes. Conclusions Although invisible, BLinD may presage type 1 MNV. BLinD volume approaches the criterion OCT drusen volume of 0.03 mm3 for AMD progression risk. BLinD culminates years of subfoveal lipid accumulation. SDD is detected relatively late in life, with currently unknown precursors. Deposit topography suggests one outer retinal lipid recycling system serving specialized cone and rod physiology, and its dysregulation in AMD is due to impaired transfer to the circulation.
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Affiliation(s)
- Ling Chen
- The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Ophthalmology, and Chongqing Eye Institute, Chongqing, China
- Department of Ophthalmology and Visual Sciences, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Jeffrey D. Messinger
- Department of Ophthalmology and Visual Sciences, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Deepayan Kar
- Department of Ophthalmology and Visual Sciences, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Jacque L. Duncan
- Department of Ophthalmology, University of California San Francisco, San Francisco, California, 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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21
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Zhang T, Kho AM, Zawadzki RJ, Jonnal RS, Yiu G, Srinivasan VJ. Visible light OCT improves imaging through a highly scattering retinal pigment epithelial wall. OPTICS LETTERS 2020; 45:5945-5948. [PMID: 33137037 PMCID: PMC7864585 DOI: 10.1364/ol.405398] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Accepted: 09/21/2020] [Indexed: 05/15/2023]
Abstract
Here we provide a counter-example to the conventional wisdom in biomedical optics that longer wavelengths aid deeper imaging in tissue. Specifically, we investigate visible light optical coherence tomography of Bruch's membrane (BM) in the non-pathologic eyes of humans and two mouse strains. Surprisingly, we find that shorter visible wavelengths improve the visualization of BM in pigmented eyes, where it is located behind a highly scattering layer of melanosomes in the retinal pigment epithelium (RPE). Monte Carlo simulations of radiative transport suggest that, while absorption and scattering are higher at shorter wavelengths, detected multiply scattered light from the RPE is preferentially attenuated relative to detected backscattered light from the BM.
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Affiliation(s)
- Tingwei Zhang
- Department of Biomedical Engineering, University of California Davis, Davis, California 95616, USA
| | - Aaron M. Kho
- Department of Biomedical Engineering, University of California Davis, Davis, California 95616, USA
| | - Robert J. Zawadzki
- Department of Ophthalmology and Vision Science, University of California Davis, Davis School of Medicine, Sacramento, California 96817, USA
| | - Ravi S. Jonnal
- Department of Ophthalmology and Vision Science, University of California Davis, Davis School of Medicine, Sacramento, California 96817, USA
| | - Glenn Yiu
- Department of Ophthalmology and Vision Science, University of California Davis, Davis School of Medicine, Sacramento, California 96817, 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
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22
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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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Zhang T, Kho AM, Srinivasan VJ. Water wavenumber calibration for visible light optical coherence tomography. JOURNAL OF BIOMEDICAL OPTICS 2020; 25:JBO-200166LR. [PMID: 32935500 PMCID: PMC7490762 DOI: 10.1117/1.jbo.25.9.090501] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 08/28/2020] [Indexed: 06/11/2023]
Abstract
SIGNIFICANCE Visible light optical coherence tomography (OCT) is emerging for spectroscopic and ultrahigh resolution imaging, but challenges remain. Depth-dependent dispersion limits retinal image quality and current correction approaches are cumbersome. Inconsistent group refractive indices during image reconstruction also limit reproducibility. AIM To introduce and evaluate water wavenumber calibration (WWC), which corrects depth-dependent dispersion and provides an accurate depth axis in water. APPROACH Enabled by a visible light OCT spectrometer configuration with a 3- to 4-dB sensitivity roll-off over 1 mm in air across a 90-nm bandwidth, we determine the spectral phase of a 1-mm water cell, an affine function of water wavenumber. Via WWC, we reconstruct visible light OCT human retinal images with 1.3-μm depth resolution in water. RESULTS Images clearly reveal Bruch's membrane, inner plexiform layer lamination, and a thin nerve fiber layer in the temporal parafovea. WWC halves the processing time, while achieving the same image definition as an assumption-free gold standard approach, suggesting that water wavenumber is a suitable proxy for tissue wavenumber. WWC also provides a depth axis in water without explicitly assuming a group refractive index. CONCLUSIONS WWC is a simple method that helps to realize the full potential of visible light OCT.
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Affiliation(s)
- Tingwei Zhang
- University of California Davis, Department of Biomedical Engineering, Davis, California, United States
| | - Aaron M. Kho
- University of California Davis, Department of Biomedical Engineering, Davis, California, United States
| | - Vivek J. Srinivasan
- University of California Davis, Department of Biomedical Engineering, Davis, California, United States
- University of California Davis, School of Medicine, Department of Ophthalmology and Vision Science, Sacramento, California, United States
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24
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Shirazi MF, Brunner E, Laslandes M, Pollreisz A, Hitzenberger CK, Pircher M. Visualizing human photoreceptor and retinal pigment epithelium cell mosaics in a single volume scan over an extended field of view with adaptive optics optical coherence tomography. BIOMEDICAL OPTICS EXPRESS 2020; 11:4520-4535. [PMID: 32923061 PMCID: PMC7449740 DOI: 10.1364/boe.393906] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 07/13/2020] [Accepted: 07/17/2020] [Indexed: 05/18/2023]
Abstract
Using adaptive optics optical coherence tomography, human photoreceptors and retinal pigment epithelium (RPE) cells are typically visualized on a small field of view of ∼1° to 2°. In addition, volume averaging is required for visualizing the RPE cell mosaic. To increase the imaging area, we introduce a lens based spectral domain AO-OCT system that shows low aberrations within an extended imaging area of 4°×4° while maintaining a high (theoretical) transverse resolution (at >7 mm pupil diameter) in the order of 2 µm. A new concept for wavefront sensing is introduced that uses light mainly originating from the RPE layer and yields images of the RPE cell mosaic in a single volume acquisition. The capability of the instrument for in vivo imaging is demonstrated by visualizing various cell structures within the posterior retinal layers over an extended field of view.
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Affiliation(s)
- Muhammad Faizan Shirazi
- Center for Medical Physics and Biomedical
Engineering, Medical University of Vienna, Waehringer Guertel 18-20,
A-1090 Vienna, Austria
| | - Elisabeth Brunner
- Center for Medical Physics and Biomedical
Engineering, Medical University of Vienna, Waehringer Guertel 18-20,
A-1090 Vienna, Austria
| | - Marie Laslandes
- ALPAO 727 rue Aristide Bergès 38330
Montbonnot-Saint-Martin, France
| | - Andreas Pollreisz
- Department of Ophthalmology and Optometry,
Medical University of Vienna, Vienna, Waehringer Guertel 18-20, A-1090
Vienna, Austria
| | - Christoph K. Hitzenberger
- Center for Medical Physics and Biomedical
Engineering, Medical University of Vienna, Waehringer Guertel 18-20,
A-1090 Vienna, Austria
| | - Michael Pircher
- Center for Medical Physics and Biomedical
Engineering, Medical University of Vienna, Waehringer Guertel 18-20,
A-1090 Vienna, Austria
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25
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Beykin G, Norcia AM, Srinivasan VJ, Dubra A, Goldberg JL. Discovery and clinical translation of novel glaucoma biomarkers. Prog Retin Eye Res 2020; 80:100875. [PMID: 32659431 DOI: 10.1016/j.preteyeres.2020.100875] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2020] [Revised: 06/01/2020] [Accepted: 06/04/2020] [Indexed: 12/16/2022]
Abstract
Glaucoma and other optic neuropathies are characterized by progressive dysfunction and loss of retinal ganglion cells and their axons. Given the high prevalence of glaucoma-related blindness and the availability of treatment options, improving the diagnosis and precise monitoring of progression in these conditions is paramount. Here we review recent progress in the development of novel biomarkers for glaucoma in the context of disease pathophysiology and we propose future steps for the field, including integration of exploratory biomarker outcomes into prospective therapeutic trials. We anticipate that, when validated, some of the novel glaucoma biomarkers discussed here will prove useful for clinical diagnosis and prediction of progression, as well as monitoring of clinical responses to standard and investigational therapies.
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Affiliation(s)
- Gala Beykin
- Spencer Center for Vision Research at Stanford University, 2370 Watson Ct, Palo Alto, CA, 94303, USA.
| | - Anthony M Norcia
- Department of Psychology, Stanford University, 290 Jane Stanford Way, Stanford, CA, 94305, USA.
| | - Vivek J Srinivasan
- Department of Biomedical Engineering, University of California, Davis, One Shields Ave, Davis, CA, 95616, USA; Department of Ophthalmology and Vision Science, University of California Davis School of Medicine, 4610 X St, Sacramento, CA, 96817, USA.
| | - Alfredo Dubra
- Spencer Center for Vision Research at Stanford University, 2370 Watson Ct, Palo Alto, CA, 94303, USA.
| | - Jeffrey L Goldberg
- Spencer Center for Vision Research at Stanford University, 2370 Watson Ct, Palo Alto, CA, 94303, USA.
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26
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Woertz EN, Omoba BS, Dunn TM, Chiu SJ, Farsiu S, Strul S, Summers CG, Drack AV, Carroll J. Assessing Ganglion Cell Layer Topography in Human Albinism Using Optical Coherence Tomography. Invest Ophthalmol Vis Sci 2020; 61:36. [PMID: 32196097 PMCID: PMC7405956 DOI: 10.1167/iovs.61.3.36] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Purpose To test whether ganglion cell layer (GCL) and inner plexiform layer (IPL) topography is altered in albinism. Methods Optical coherence tomography scans were analyzed in 30 participants with albinism and 25 control participants. Horizontal and vertical line scans were acquired at the fovea, then strip registered and averaged. The Duke Optical Coherence Tomography Retinal Analysis Program was used to automatically segment the combined GCL and IPL and total retinal thickness, followed by program-assisted manual segmentation of the boundary between the GCL and IPL. Layer thickness and area under the curve (AUC) were calculated within 2.5 mm of the fovea. Nasal-temporal and superior-inferior asymmetry were calculated as an AUC ratio in each quadrant. Results GCL and IPL topography varied between participants. The summed AUC in all quadrants was similar between groups for both the GCL (P = 0.84) and IPL (P = 0.08). Both groups showed nasal-temporal asymmetry in the GCL, but only participants with albinism had nasal-temporal asymmetry in the IPL. Nasal-temporal asymmetry was greater in albinism for both the GCL (P < 0.0001) and the IPL (P = 0.0006). The GCL usually comprised a greater percentage of the combined GCL and IPL in controls than in albinism. Conclusions The GCL and IPL have greater structural variability than previously reported. GCL and IPL topography are significantly altered in albinism, which suggests differences in the spatial distribution of retinal ganglion cells. This finding provides insight into foveal development and structure-function relationships in foveal hypoplasia.
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Borkovkina S, Camino A, Janpongsri W, Sarunic MV, Jian Y. Real-time retinal layer segmentation of OCT volumes with GPU accelerated inferencing using a compressed, low-latency neural network. BIOMEDICAL OPTICS EXPRESS 2020; 11:3968-3984. [PMID: 33014579 PMCID: PMC7510892 DOI: 10.1364/boe.395279] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 06/18/2020] [Accepted: 06/18/2020] [Indexed: 05/18/2023]
Abstract
Segmentation of retinal layers in optical coherence tomography (OCT) is an essential step in OCT image analysis for screening, diagnosis, and assessment of retinal disease progression. Real-time segmentation together with high-speed OCT volume acquisition allows rendering of en face OCT of arbitrary retinal layers, which can be used to increase the yield rate of high-quality scans, provide real-time feedback during image-guided surgeries, and compensate aberrations in adaptive optics (AO) OCT without using wavefront sensors. We demonstrate here unprecedented real-time OCT segmentation of eight retinal layer boundaries achieved by 3 levels of optimization: 1) a modified, low complexity, neural network structure, 2) an innovative scheme of neural network compression with TensorRT, and 3) specialized GPU hardware to accelerate computation. Inferencing with the compressed network U-NetRT took 3.5 ms, improving by 21 times the speed of conventional U-Net inference without reducing the accuracy. The latency of the entire pipeline from data acquisition to inferencing was only 41 ms, enabled by parallelized batch processing. The system and method allow real-time updating of en face OCT and OCTA visualizations of arbitrary retinal layers and plexuses in continuous mode scanning. To the best our knowledge, our work is the first demonstration of an ophthalmic imager with embedded artificial intelligence (AI) providing real-time feedback.
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Affiliation(s)
| | - Acner Camino
- Casey Eye Institute, Oregon Health & Science University, Portland, OR 27239, USA
| | - Worawee Janpongsri
- Department of Engineering Science, Simon Fraser University, Burnaby, Canada
| | - Marinko V. Sarunic
- Department of Engineering Science, Simon Fraser University, Burnaby, Canada
| | - Yifan Jian
- Casey Eye Institute, Oregon Health & Science University, Portland, OR 27239, USA
- Department of Biomedical Engineering, Oregon Health & Science University, Portland, OR 97239, USA
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28
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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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29
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Song W, Shao W, Yi W, Liu R, Desai M, Ness S, Yi J. Visible light optical coherence tomography angiography (vis-OCTA) facilitates local microvascular oximetry in the human retina. BIOMEDICAL OPTICS EXPRESS 2020; 11:4037-4051. [PMID: 33014584 PMCID: PMC7510897 DOI: 10.1364/boe.395843] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 06/18/2020] [Accepted: 06/22/2020] [Indexed: 05/06/2023]
Abstract
We report herein the first visible light optical coherence tomography angiography (vis-OCTA) for human retinal imaging. Compared to the existing vis-OCT systems, we devised a spectrometer with a narrower bandwidth to increase the spectral power density for OCTA imaging, while retaining the major spectral contrast in the blood. We achieved a 100 kHz A-line rate, the fastest acquisition speed reported so far for human retinal vis-OCT. We rigorously optimized the imaging protocol such that a single acquisition took < 6 seconds with a field of view (FOV) of 3×7.8 mm2. The angiography enables accurate localization of microvasculature down to the capillary level and thus enables oximetry at vessels < 100 µm in diameter. We demonstrated microvascular hemoglobin oxygen saturation (sO2) at the feeding and draining vessels at the perifoveal region. The longitudinal repeatability was assessed by < 5% coefficient of variation (CV). The unique capabilities of our vis-OCTA system may allow studies on the role of microvascular oxygen in various retinal pathologies.
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Affiliation(s)
- Weiye Song
- Department of Medicine, Boston University School of Medicine, Boston Medical Center, Boston 02118, USA
| | - Wenjun Shao
- Department of Medicine, Boston University School of Medicine, Boston Medical Center, Boston 02118, USA
| | - Wei Yi
- Department of Medicine, Boston University School of Medicine, Boston Medical Center, Boston 02118, USA
| | - Rongrong Liu
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA
| | - Manishi Desai
- Department of Ophthalmology, Boston University School of Medicine, Boston Medical Center, Boston 02118, USA
| | - Steven Ness
- Department of Ophthalmology, Boston University School of Medicine, Boston Medical Center, Boston 02118, USA
| | - Ji Yi
- Department of Medicine, Boston University School of Medicine, Boston Medical Center, Boston 02118, USA
- Department of Biomedical Engineering, Boston University, Boston 02118, USA
- Department of Electronic and Computer Engineering, Boston University, Boston 02118, USA
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30
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Retinal capillary oximetry with visible light optical coherence tomography. Proc Natl Acad Sci U S A 2020; 117:11658-11666. [PMID: 32398376 DOI: 10.1073/pnas.1918546117] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Assessing oxygen saturation (sO2) remains challenging but is nonetheless necessary for understanding retinal metabolism. We and others previously achieved oximetry on major retinal vessels and measured the total retinal oxygen metabolic rate in rats using visible-light optical coherence tomography. Here we extend oximetry measurements to capillaries and investigate all three retinal vascular plexuses by amplifying and extracting the spectroscopic signal from each capillary segment under the guidance of optical coherence tomography (OCT) angiography. Using this approach, we measured capillary sO2 in the retinal circulation in rats, demonstrated reproducibility of the results, validated the measurements in superficial capillaries with known perfusion pathways, and determined sO2 responses to hypoxia and hyperoxia in the different retinal capillary beds. OCT capillary oximetry has the potential to provide new insights into the retinal circulation in the normal eye as well as in retinal vascular diseases.
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31
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Pi S, Hormel TT, Wei X, Cepurna W, Morrison JC, Jia Y. Imaging retinal structures at cellular-level resolution by visible-light optical coherence tomography. OPTICS LETTERS 2020; 45:2107-2110. [PMID: 32236080 PMCID: PMC8575555 DOI: 10.1364/ol.386454] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Accepted: 03/05/2020] [Indexed: 05/10/2023]
Abstract
In vivo high-resolution images are the most direct way to understand retinal function and diseases. Here we report the use of visible-light optical coherence tomography with volumetric registration and averaging to achieve cellular-level retinal structural imaging in a rat eye, covering the entire depth of the retina. Vitreous fibers, nerve fiber bundles, and vasculature were clearly revealed, as well as at least three laminar sublayers in the inner plexiform layer. We also successfully visualized ganglion cell somas in the ganglion cell layer, cells in the inner nuclear layer, and photoreceptors in the outer nuclear layer and ellipsoid zone. This technique provides, to the best of our knowledge, a new means to visualize the retina in vivo at a cellular resolution and may enable detection or discovery of cellular neuronal biomarkers to help better diagnose ocular disease.
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Affiliation(s)
- Shaohua Pi
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon 97239, USA
| | - Tristan T. Hormel
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon 97239, USA
| | - Xiang Wei
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon 97239, USA
| | - William Cepurna
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon 97239, USA
| | - John C. Morrison
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon 97239, USA
| | - Yali Jia
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon 97239, USA
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32
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Liu R, Cheng S, Tian L, Yi J. Deep spectral learning for label-free optical imaging oximetry with uncertainty quantification. LIGHT, SCIENCE & APPLICATIONS 2019; 8:102. [PMID: 31754429 PMCID: PMC6864044 DOI: 10.1038/s41377-019-0216-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 10/17/2019] [Accepted: 11/01/2019] [Indexed: 05/06/2023]
Abstract
Measurement of blood oxygen saturation (sO2) by optical imaging oximetry provides invaluable insight into local tissue functions and metabolism. Despite different embodiments and modalities, all label-free optical-imaging oximetry techniques utilize the same principle of sO2-dependent spectral contrast from haemoglobin. Traditional approaches for quantifying sO2 often rely on analytical models that are fitted by the spectral measurements. These approaches in practice suffer from uncertainties due to biological variability, tissue geometry, light scattering, systemic spectral bias, and variations in the experimental conditions. Here, we propose a new data-driven approach, termed deep spectral learning (DSL), to achieve oximetry that is highly robust to experimental variations and, more importantly, able to provide uncertainty quantification for each sO2 prediction. To demonstrate the robustness and generalizability of DSL, we analyse data from two visible light optical coherence tomography (vis-OCT) setups across two separate in vivo experiments on rat retinas. Predictions made by DSL are highly adaptive to experimental variabilities as well as the depth-dependent backscattering spectra. Two neural-network-based models are tested and compared with the traditional least-squares fitting (LSF) method. The DSL-predicted sO2 shows significantly lower mean-square errors than those of the LSF. For the first time, we have demonstrated en face maps of retinal oximetry along with a pixel-wise confidence assessment. Our DSL overcomes several limitations of traditional approaches and provides a more flexible, robust, and reliable deep learning approach for in vivo non-invasive label-free optical oximetry.
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Affiliation(s)
- Rongrong Liu
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208 USA
| | - Shiyi Cheng
- Department of Electrical and Computer Engineering, Boston University, Boston, MA 02215 USA
| | - Lei Tian
- Department of Electrical and Computer Engineering, Boston University, Boston, MA 02215 USA
| | - Ji Yi
- Department of Electrical and Computer Engineering, Boston University, Boston, MA 02215 USA
- Department of Biomedical Engineering, Boston University, Boston, MA 02215 USA
- Department of Medicine, Boston University School of Medicine, Boston Medical Center, Boston, MA 02118 USA
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