1
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Cheng J, Zhao H, Jiang C, Kong X, Sun X. Change of Retinal Vessels in Different Sectors of the Parapapillary Area in Primary Open-Angle Glaucoma. Front Med (Lausanne) 2021; 8:705829. [PMID: 34307429 PMCID: PMC8295556 DOI: 10.3389/fmed.2021.705829] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Accepted: 06/11/2021] [Indexed: 11/24/2022] Open
Abstract
Purpose: To investigate the changes in the retinal vessels (RVs) in different sectors in patients with primary open-angle glaucoma (POAG), and their possible correlations with retinal nerve fiber layer thickness (RNFLT) and visual-field defects in the temporal parapapillary region. Methods: The RV diameters, RNFLTs, and visual-field parameters were measured. The temporal parapapillary region was divided into the temporal (T, 315°-45°), temporal superior (TS, 45°-90°), and temporal inferior sectors (TI, 270°-315°). The changes in the RV diameters in each sector were determined, and their relationships with RNFLT, the mean deviation (MD), and visual field sensitivity (VFS) were examined. Results: Fifty POAG patients (50 eyes) and 50 healthy subjects (50 eyes) were included. Compared with the healthy subjects, the POAG group had a significantly smaller accumulated parapapillary RV diameter (P < 0.001), which was positively correlated with the MD and RNFLT. When the different temporal sectors were examined, the accumulated RV diameters were significantly smaller in the POAG group than in the healthy controls in the TI and T sectors, but not in the TS sector. The accumulated diameters in the TI and T sectors were correlated with the corresponding RNFLTs (all P < 0.05), but only the accumulated diameter in the TI sector was correlated with the VFS. Conclusions: In POAG, the changes in the RVs differed between different temporal sectors, with the most prominent changes occurring in the TI and T sectors.
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Affiliation(s)
- Jingyi Cheng
- Department of Ophthalmology and Visual Science, Eye, Ear, Nose and Throat Hospital, Fudan University, Shanghai, China.,Key Laboratory of Myopia, Ministry of Health, Fudan University, Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China
| | - Hongmei Zhao
- Department of Ophthalmology and Visual Science, Eye, Ear, Nose and Throat Hospital, Fudan University, Shanghai, China.,Key Laboratory of Myopia, Ministry of Health, Fudan University, Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China
| | - Chunhui Jiang
- Department of Ophthalmology and Visual Science, Eye, Ear, Nose and Throat Hospital, Fudan University, Shanghai, China.,Key Laboratory of Myopia, Ministry of Health, Fudan University, Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China
| | - Xiangmei Kong
- Department of Ophthalmology and Visual Science, Eye, Ear, Nose and Throat Hospital, Fudan University, Shanghai, China.,Key Laboratory of Myopia, Ministry of Health, Fudan University, Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China
| | - Xinghuai Sun
- Department of Ophthalmology and Visual Science, Eye, Ear, Nose and Throat Hospital, Fudan University, Shanghai, China.,Key Laboratory of Myopia, Ministry of Health, Fudan University, Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China.,State Key Laboratory of Medical Neurobiology, Institutes of Brain Science, Fudan University, Shanghai, China
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2
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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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3
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DOU PENG, ZHANG YANG, ZHENG RUI, YE YU, MAO JIANBO, LIU LEI, WU MING, SUN MINGZHAI. RETINAL IMAGING AND ANALYSIS USING MACHINE LEARNING WITH INFORMATION FUSION OF THE FUNCTIONAL AND STRUCTURAL FEATURES BASED ON A DUAL-MODAL FUNDUS CAMERA. J MECH MED BIOL 2021. [DOI: 10.1142/s0219519421500305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Retinal diseases and systemic diseases, such as diabetic retinopathy (DR) and Alzheimer’s disease, may manifest themselves in the retina, changing the retinal oxygen saturation ([Formula: see text]) level or the retinal vascular structures. Recent studies explored the correlation of diseases with either retina vascular structures or [Formula: see text] level, but not both due to the lack of proper instrument or methodology. In this study, we applied a dual-modal fundus camera and developed a deep learning-based analysis method to simultaneously acquire and quantify the [Formula: see text] and vascular structures. Deep learning was used to automatically locate the optic discs and segment arterioles and venules of the blood vessels. We then sought to apply machine learning methods, such as random forest (RF) and support vector machine (SVM), to fuse the [Formula: see text] level and retinal vessel parameters as different features to discriminate against the disease from the healthy controls. We showed that the fusion of the functional (oxygen saturation) and structural (vascular parameters) features offers better performance to classify diseased and healthy subjects. For example, we gained a 13.8% and 2.0% increase in the accuracy with fusion using the RF and SVM to classify the nonproliferative DR and the healthy controls.
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Affiliation(s)
- PENG DOU
- Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei 230026, P. R. China
| | - YANG ZHANG
- The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui 230001, P. R. China
| | - RUI ZHENG
- Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei 230026, P. R. China
| | - YU YE
- Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei 230026, P. R. China
| | - JIANBO MAO
- Eye Hospital of Wenzhou Medical University, Wenzhou Medical University, Wenzhou, P. R. China
| | - LEI LIU
- Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei 230026, P. R. China
| | - MING WU
- The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui 230001, P. R. China
| | - MINGZHAI SUN
- Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei 230026, P. R. China
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4
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Deep multispectral image registration network. Comput Med Imaging Graph 2021; 87:101815. [PMID: 33418174 DOI: 10.1016/j.compmedimag.2020.101815] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Revised: 09/27/2020] [Accepted: 10/30/2020] [Indexed: 11/24/2022]
Abstract
Multispectral imaging (MSI) of the ocular fundus provides a sequence of narrow-band images to show the different depths in the retina and choroid. One challenge in analyzing MSI images comes from the image-to-image spatial misalignment, which occurs because the acquisition time of eye MSI images is commonly longer than the natural time scale of the eye's saccadic movement. It is necessary to align images because ophthalmologists usually overlay two of the images to analyze specific features when analyzing MSI images. In this paper, we propose a weakly supervised MSI image registration network, called MSI-R-NET, for multispectral fundus image registration. Compared to other deep-learning-based registration methods, MSI-R-NET utilizes the blood vessel segmentation label to provide spatial correspondence. In addition, we employ a feature equilibrium module to connect the aggregating layers better, and propose a multiresolution auto-context structure to adapt the registration task. In the testing stage, given a new pair of MSI images, the trained model can predict the pixelwise spatial correspondence without labeled blood vessel information. The experimental results demonstrate that the proposed segmentation-driven registration method is highly accurate.
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5
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Rehman AU, Qureshi SA. A review of the medical hyperspectral imaging systems and unmixing algorithms' in biological tissues. Photodiagnosis Photodyn Ther 2020; 33:102165. [PMID: 33383204 DOI: 10.1016/j.pdpdt.2020.102165] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 12/18/2020] [Accepted: 12/21/2020] [Indexed: 01/27/2023]
Abstract
Hyperspectral fluorescence imaging (HFI) is a well-known technique in the medical research field and is considered a non-invasive tool for tissue diagnosis. This review article gives a brief introduction to acquisition methods, including the image preprocessing methods, feature selection and extraction methods, data classification techniques and medical image analysis along with recent relevant references. The process of fusion of unsupervised unmixing techniques with other classification methods, like the combination of support vector machine with an artificial neural network, the latest snapshot Hyperspectral imaging (HSI) and vortex analysis techniques are also outlined. Finally, the recent applications of hyperspectral images in cellular differentiation of various types of cancer are discussed.
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Affiliation(s)
- Aziz Ul Rehman
- Agri & Biophotonics Division, National Institute of Lasers and Optronics College, PIEAS, 45650, Islamabad, Pakistan; Department of Physics and Astronomy Macquarie University, Sydney, 2109, New South Wales, Australia.
| | - Shahzad Ahmad Qureshi
- Department of Computer and Information Sciences, Pakistan Institute of Engineering and Applied Sciences (PIEAS), Islamabad, 45650, Pakistan
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Lemmens S, Van Eijgen J, Van Keer K, Jacob J, Moylett S, De Groef L, Vancraenendonck T, De Boever P, Stalmans I. Hyperspectral Imaging and the Retina: Worth the Wave? Transl Vis Sci Technol 2020; 9:9. [PMID: 32879765 PMCID: PMC7442879 DOI: 10.1167/tvst.9.9.9] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Accepted: 06/23/2020] [Indexed: 02/07/2023] Open
Abstract
Purpose Hyperspectral imaging is gaining attention in the biomedical field because it generates additional spectral information to study physiological and clinical processes. Several technologies have been described; however an independent, systematic literature overview is lacking, especially in the field of ophthalmology. This investigation is the first to systematically overview scientific literature specifically regarding retinal hyperspectral imaging. Methods A systematic literature review was conducted, in accordance with PRISMA Statement 2009 criteria, in four bibliographic databases: Medline, Embase, Cochrane Database of Systematic Reviews, and Web of Science. Results Fifty-six articles were found that meet the review criteria. A range of techniques was reported: Fourier analysis, liquid crystal tunable filters, tunable laser sources, dual-slit monochromators, dispersive prisms and gratings, computed tomography, fiber optics, and Fabry-Perrot cavity filter covered complementary metal oxide semiconductor. We present a narrative synthesis and summary tables of findings of the included articles, because methodologic heterogeneity and diverse research topics prevented a meta-analysis being conducted. Conclusions Application in ophthalmology is still in its infancy. Most previous experiments have been performed in the field of retinal oximetry, providing valuable information in the diagnosis and monitoring of various ocular diseases. To date, none of these applications have graduated to clinical practice owing to the lack of sufficiently large validation studies. Translational Relevance Given the promising results that smaller studies show for hyperspectral imaging (e.g., in Alzheimer's disease), advanced research in larger validation studies is warranted to determine its true clinical potential.
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Affiliation(s)
- Sophie Lemmens
- University Hospitals UZ Leuven, Department of Ophthalmology, Leuven, Belgium
- KU Leuven, Biomedical Sciences Group, Department of Neurosciences, Research Group Ophthalmology, Leuven, Belgium
- VITO (Flemish Institute for Technological Research), Health Unit, Boeretang, Belgium
| | - Jan Van Eijgen
- University Hospitals UZ Leuven, Department of Ophthalmology, Leuven, Belgium
- KU Leuven, Biomedical Sciences Group, Department of Neurosciences, Research Group Ophthalmology, Leuven, Belgium
- VITO (Flemish Institute for Technological Research), Health Unit, Boeretang, Belgium
| | - Karel Van Keer
- University Hospitals UZ Leuven, Department of Ophthalmology, Leuven, Belgium
- KU Leuven, Biomedical Sciences Group, Department of Neurosciences, Research Group Ophthalmology, Leuven, Belgium
| | - Julie Jacob
- University Hospitals UZ Leuven, Department of Ophthalmology, Leuven, Belgium
- KU Leuven, Biomedical Sciences Group, Department of Neurosciences, Research Group Ophthalmology, Leuven, Belgium
| | - Sinéad Moylett
- Department of Psychiatry, University of Cambridge School of Clinical Medicine, Cambridge Biomedical Campus, Cambridge, UK
| | - Lies De Groef
- Neural Circuit Development and Regeneration Research Group, Department of Biology, KU Leuven, Leuven, Belgium
| | - Toon Vancraenendonck
- VITO (Flemish Institute for Technological Research), Health Unit, Boeretang, Belgium
| | - Patrick De Boever
- VITO (Flemish Institute for Technological Research), Health Unit, Boeretang, Belgium
- Hasselt University, Centre of Environmental Sciences, Agoralaan, Belgium
| | - Ingeborg Stalmans
- University Hospitals UZ Leuven, Department of Ophthalmology, Leuven, Belgium
- KU Leuven, Biomedical Sciences Group, Department of Neurosciences, Research Group Ophthalmology, Leuven, Belgium
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7
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8
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Retinal oximetry: Metabolic imaging for diseases of the retina and brain. Prog Retin Eye Res 2019; 70:1-22. [DOI: 10.1016/j.preteyeres.2019.04.001] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 03/27/2019] [Accepted: 04/10/2019] [Indexed: 12/20/2022]
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9
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Colligris P, Perez de Lara MJ, Colligris B, Pintor J. Ocular Manifestations of Alzheimer's and Other Neurodegenerative Diseases: The Prospect of the Eye as a Tool for the Early Diagnosis of Alzheimer's Disease. J Ophthalmol 2018; 2018:8538573. [PMID: 30151279 PMCID: PMC6091327 DOI: 10.1155/2018/8538573] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 06/07/2018] [Accepted: 06/26/2018] [Indexed: 12/20/2022] Open
Abstract
Dementia, including Alzheimer's disease (AD), is a major disorder, leading to several ocular manifestations amongst the elderly population. These visual disorders may be due to retinal nerve degenerative changes, including nerve fibre layer thinning, degeneration of retinal ganglion cells, and changes to vascular parameters. There is no cure for Alzheimer's, but medicines can slow down the development of many of the classic symptoms, such as loss of memory and communication skills, mood swings, and depression. The disease diagnosis is difficult, and it is only possible through PET scans of the brain, detecting evidence of the accumulation of amyloid and tau. PET is expensive and invasive, requiring the injection of radioactive tracers, which bind with these proteins and glow during scanning. Recently, scientists developed promising eye-scan techniques that may detect Alzheimer's disease at its earliest stage, before major symptoms appear, leading to improved management of the disease symptoms. In this review, we are discussing the visual abnormalities of Alzheimer's and other neurodegenerative diseases, focused on ocular functional-visual-structural biomarkers, retinal pathology, and potential novel diagnostic tools.
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Affiliation(s)
- Pade Colligris
- Universidad Alfonso X, Madrid, Spain
- Ocupharm Diagnostics SL, Madrid, Spain
| | | | - Basilio Colligris
- Ocupharm Diagnostics SL, Madrid, Spain
- Universidad Complutense de Madrid, Madrid, Spain
| | - Jesus Pintor
- Ocupharm Diagnostics SL, Madrid, Spain
- Universidad Complutense de Madrid, Madrid, Spain
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10
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Li Y, Xu J, Xia R, Huang Q, Xie W, Li X. Extreme-constrained spatial-spectral corner detector for image-level hyperspectral image classification. Pattern Recognit Lett 2018. [DOI: 10.1016/j.patrec.2018.03.022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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11
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Heitmar R, Vekria P, Cubbidge RP. Regulation of oxygen saturation in retinal blood vessels in response to dynamic exercise. Acta Ophthalmol 2018; 96:e298-e303. [PMID: 29098810 DOI: 10.1111/aos.13576] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 08/01/2017] [Indexed: 11/29/2022]
Abstract
PURPOSE To evaluate the impact of dynamic exercise on retinal vessel oxygen saturation in healthy individuals. METHODS Twenty-six healthy participants underwent moderate dynamic exercise (modified Master's two-step exercise). In all subjects, intraocular pressures (IOP), systolic and diastolic blood pressures (SBP and DBP), retinal vessel calibres and retinal arterial and venous oxygen saturation were measured at baseline, immediately following exercise and 15 min postexercise. RESULTS Moderate dynamic exercise increased SBP and DBP immediately postexercise (SBP: 116 (±13) mmHg to 150 (±21) mmHg; p < 0.001 and DBP: 69 (±10) mmHg to 74 (±10); p < 0.001), while IOP decreased by an average of 2 mmHg (baseline: 13 (±3) mmHg)) immediately postexercise (11 (±2) mmHg). Oxygen saturation in retinal arteries remained unchanged (baseline = 93 ± 8%; immediately postexercise = 94 ± 9% and 15 min postexercise = 96 ± 8%; p = 0.069), but increased in retinal veins immediately postexercise and did not return to baseline values within 15 min postexercise (baseline = 54 ± 12%; immediately postexercise = 56 ± 15%; 15 min postexercise=57 ± 12%; p = 0.036). CONCLUSION There is a mild increase in retinal venous oxygen saturation and there is a trend towards an increase in arterial saturation in otherwise healthy individuals following dynamic exercise.
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Affiliation(s)
- Rebekka Heitmar
- School of Life and Health Sciences; Aston University; Birmingham UK
| | - Pravin Vekria
- School of Life and Health Sciences; Aston University; Birmingham UK
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12
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Chen S, Shu X, Nesper PL, Liu W, Fawzi AA, Zhang HF. Retinal oximetry in humans using visible-light optical coherence tomography [Invited]. BIOMEDICAL OPTICS EXPRESS 2017; 8:1415-1429. [PMID: 28663838 PMCID: PMC5480553 DOI: 10.1364/boe.8.001415] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Revised: 02/01/2017] [Accepted: 02/01/2017] [Indexed: 05/18/2023]
Abstract
We measured hemoglobin oxygen saturation (sO2) in the retinal circulation in healthy humans using visible-light optical coherence tomography (vis-OCT). The measurements showed clear oxygenation differences between central retinal arteries and veins close to the optic nerve head. Spatial variations at different vascular branching levels were also revealed. In addition, we presented theoretical and experimental results to establish that noises in OCT intensity followed Rice distribution. We used this knowledge to retrieve unbiased estimation of true OCT intensity to improve the accuracy of vis-OCT oximetry, which had inherently lower signal-to-nose ratio from human eyes due to safety and comfort limitations. We demonstrated that the new statistical-fitting sampling strategy could reduce the estimation error in sO2 by three percentage points (pp). The presented work aims to provide a foundation for using vis-OCT to achieve accurate retinal oximetry in clinical settings.
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Affiliation(s)
- Siyu Chen
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA
| | - Xiao Shu
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA
| | - Peter L. Nesper
- Department of Ophthalmology, Northwestern University, Chicago, IL 60611, USA
| | - Wenzhong Liu
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA
- Currently with Opticent Health, Evanston, IL 60208, USA
| | - Amani A. Fawzi
- Department of Ophthalmology, Northwestern University, Chicago, IL 60611, USA
| | - Hao F. Zhang
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA
- Department of Ophthalmology, Northwestern University, Chicago, IL 60611, USA
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13
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Shahidi AM, Hudson C, Tayyari F, Flanagan JG. Retinal Oxygen Saturation in Patients with Primary Open-angle Glaucoma Using a Non-flash Hypespectral Camera. Curr Eye Res 2016; 42:557-561. [DOI: 10.1080/02713683.2016.1217544] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Ayda M. Shahidi
- School of Optometry and Vision Science, University of Waterloo, Waterloo, ON, Canada
- Krembil Research Institute, Department of Ophthalmology, Toronto, ON, Canada
| | - Chris Hudson
- School of Optometry and Vision Science, University of Waterloo, Waterloo, ON, Canada
- Krembil Research Institute, Department of Ophthalmology, Toronto, ON, Canada
| | - Faryan Tayyari
- School of Optometry and Vision Science, University of Waterloo, Waterloo, ON, Canada
| | - John G. Flanagan
- Krembil Research Institute, Department of Ophthalmology, Toronto, ON, Canada
- School of Optometry, University of California Berkeley, Berkley, CA, USA
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Jørgensen CM, Bek T. Lack of differences in the regional variation of oxygen saturation in larger retinal vessels in diabetic maculopathy and proliferative diabetic retinopathy. Br J Ophthalmol 2016; 101:752-757. [PMID: 27553678 DOI: 10.1136/bjophthalmol-2016-308894] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Revised: 07/12/2016] [Accepted: 08/03/2016] [Indexed: 11/03/2022]
Abstract
BACKGROUND Diabetic retinopathy is characterised by morphological lesions in the ocular fundus related to disturbances in retinal blood flow. The two vision threatening forms of retinopathy show specific patterns of distribution of retinal lesions with proliferative diabetic retinopathy (PDR) developing secondary to ischaemia and hypoxia in the retinal periphery and diabetic maculopathy (DM) developing secondary to hyperperfusion and increased vascular permeability in the macular area. These differences in the distribution of retinal lesions might be reflected in regional differences in oxygen saturation in the larger retinal vessels. METHODS Dual-wavelength retinal oximetry was performed in 30 normal persons, 30 patients with DM and 30 patients with PDR, and the oxygen saturation was measured in peripapillary vessels supplying the four retinal quadrants and in branches from the upper temporal arcades supplying, respectively, the macular area and the retinal periphery. RESULTS The overall oxygen saturation was significantly higher in diabetic patients than in normal persons and the arteriovenous (AV) saturation difference significantly lower in the patients with DM. The regional variation in oxygen saturation was similar in the three studied groups with a decreasing saturation from the upper nasal through the lower nasal, lower temporal and the upper temporal peripapillary vessels, and with a significantly higher oxygen saturation in venules draining the macular area than in venules draining the retinal periphery. CONCLUSIONS The regional differences in retinal lesions in vision threatening diabetic retinopathy are not reflected in regional differences in the oxygen saturation of larger retinal vessels. The development of vision threatening diabetic retinopathy depends on other factors, such as, for example, regional differences in the retinal microcirculation.
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Affiliation(s)
| | - Toke Bek
- Department of Ophthalmology, Aarhus University Hospital, Aarhus C, Denmark
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15
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Nakano Y, Shimazaki T, Kobayashi N, Miyoshi Y, Ono A, Kobayashi M, Shiragami C, Hirooka K, Tsujikawa A. Retinal Oximetry in a Healthy Japanese Population. PLoS One 2016; 11:e0159650. [PMID: 27434373 PMCID: PMC4951009 DOI: 10.1371/journal.pone.0159650] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2015] [Accepted: 07/06/2016] [Indexed: 01/08/2023] Open
Abstract
Purpose To establish the normative database of retinal oximetry using Oxymap T1 in a healthy Japanese population, and study the reproducibility of the measurements in Japanese. Methods We measured oxygen saturation in the major retinal vessels with Oxymap T1 in 252 eyes of 252 healthy Japanese subjects. Fundus images acquired using Oxymap T1 were processed using built-in Oxymap Analyzer software. Reproducibility of retinal oximetry was investigated using 20 eyes of 20 healthy subjects. Results The mean retinal oxygen saturation of 4 quadrants in healthy Japanese was 97.0 ± 6.9% in arteries and 52.8 ± 8.3% in veins. The mean arteriovenous difference in oxygen saturation was 44.2 ± 9.2%. Both arterial and venous oxygen saturation were significantly lower in the temporal side of the retina, especially in the temporal-inferior vessels. However, the arteriovenous difference in oxygen saturation was limited in the 4 quadrants. Interphotograph, intervisit, and interevaluator intraclass correlation coefficients were 0.936–0.979, 0.809–0.837, and 0.732–0.947, respectively. In the major retinal arteries, oxygen saturation increased with age (r = 0.18, p<0.01), at a rate of 0.67% per 10 years. However, venous oxygen saturation showed no correlation with age. Conclusions This study provides the normative database for the Japanese population. The arterial saturation value appears to be higher than other previous studies. Mean retinal oximetry in 4 quadrants with Oxymap T1 has high reproducibility.
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Affiliation(s)
- Yuki Nakano
- Department of Ophthalmology, Kagawa University Faculty of Medicine, Miki, Japan
- * E-mail:
| | - Takeru Shimazaki
- Department of Ophthalmology, Kagawa University Faculty of Medicine, Miki, Japan
| | - Nobuko Kobayashi
- Department of Ophthalmology, Kagawa University Faculty of Medicine, Miki, Japan
| | - Yukiko Miyoshi
- Department of Ophthalmology, Kagawa University Faculty of Medicine, Miki, Japan
| | - Aoi Ono
- Department of Ophthalmology, Kagawa University Faculty of Medicine, Miki, Japan
| | - Mamoru Kobayashi
- Department of Ophthalmology, Kagawa University Faculty of Medicine, Miki, Japan
| | - Chieko Shiragami
- Department of Ophthalmology, Kagawa University Faculty of Medicine, Miki, Japan
| | - Kazuyuki Hirooka
- Department of Ophthalmology, Kagawa University Faculty of Medicine, Miki, Japan
| | - Akitaka Tsujikawa
- Department of Ophthalmology, Kagawa University Faculty of Medicine, Miki, Japan
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16
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Ramm L, Jentsch S, Peters S, Sauer L, Augsten R, Hammer M. Dependence of diameters and oxygen saturation of retinal vessels on visual field damage and age in primary open-angle glaucoma. Acta Ophthalmol 2016; 94:276-81. [PMID: 25876673 DOI: 10.1111/aos.12727] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Accepted: 02/24/2015] [Indexed: 01/03/2023]
Abstract
PURPOSE To investigate the interrelationship between the oxygen supply of the retina and its regulation with the severity of primary open-angle glaucoma (POAG). METHODS Central retinal artery (CRAE) and vein (CRVE) diameters and oxygen saturation of peripapillary retinal vessels in 41 patients suffering from POAG (64.1 ± 12.9 years) and 40 healthy volunteers (63.6 ± 14.1 years) were measured using the retinal vessel analyzer. All measures were taken before and during flicker light stimulation. The mean retinal nerve fiber layer thickness (RNFLT) was determined by OCT and the visual field mean defect (MD) was identified using perimetry. RESULTS In glaucoma patients, CRAE (r = -0.48 p = 0.002) and CRVE (r = -0.394 p = 0.014) at baseline were inversely related to MD, while arterial and venous oxygen saturation showed no significant dependence on the severity of the damage. However, the flicker light-induced change in arterio-venous difference in oxygen saturation was correlated with the MD (r = 0.358 p = 0.027). The diameters of arteries and veins at baseline decreased with reduction of the mean RNFLT (arteries: r = 0.718 p < 0.001; veins: r = 0.685 p < 0.001). CONCLUSION Vessel diameters showed a strong correlation with RNFLT and MD. This, as well as the reduction of stimulation-induced change in arterio-venous oxygen saturation difference with visual field loss, may be explained by a reduction of the retinal metabolic demand with progressive loss of neuronal tissue in glaucoma.
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Affiliation(s)
- Lisa Ramm
- Department of Ophthalmology; University Hospital Jena; Jena Germany
| | - Susanne Jentsch
- Department of Ophthalmology; University Hospital Jena; Jena Germany
| | - Sven Peters
- Department of Ophthalmology; University Hospital Jena; Jena Germany
| | - Lydia Sauer
- Department of Ophthalmology; University Hospital Jena; Jena Germany
| | - Regine Augsten
- Department of Ophthalmology; University Hospital Jena; Jena Germany
| | - Martin Hammer
- Department of Ophthalmology; University Hospital Jena; Jena Germany
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Desjardins M, Sylvestre JP, Jafari R, Kulasekara S, Rose K, Trussart R, Arbour JD, Hudson C, Lesage F. Preliminary investigation of multispectral retinal tissue oximetry mapping using a hyperspectral retinal camera. Exp Eye Res 2016; 146:330-340. [PMID: 27060375 DOI: 10.1016/j.exer.2016.04.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2015] [Revised: 03/31/2016] [Accepted: 04/01/2016] [Indexed: 10/22/2022]
Abstract
Oximetry measurement of principal retinal vessels represents a first step towards understanding retinal metabolism, but the technique could be significantly enhanced by spectral imaging of the fundus outside of main vessels. In this study, a recently developed Hyperspectral Retinal Camera was used to measure relative oximetric (SatO2) and total hemoglobin (HbT) maps of the retina, outside of large vessels, in healthy volunteers at baseline (N = 7) and during systemic hypoxia (N = 11), as well as in patients with glaucoma (N = 2). Images of the retina, on a field of view of ∼30°, were acquired between 500 and 600 nm with 2 and 5 nm steps, in under 3 s. The reflectance spectrum from each pixel was fitted to a model having oxy- and deoxyhemoglobin as the main absorbers and scattering modeled by a power law, yielding estimates of relative SatO2 and HbT over the fundus. Average optic nerve head (ONH) saturation over 8 eyes was 68 ± 5%. During systemic hypoxia, mean ONH saturation decreased by 12.5% on average. Upon further development and validation, the relative SatO2 and HbT maps of microvasculature obtained with this imaging system could ultimately contribute to the diagnostic and management of diseases affecting the ONH and retina.
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Affiliation(s)
- Michèle Desjardins
- École Polytechnique de Montréal, Institut de génie biomédical, Département de Génie électrique, 2900, boul. Édouard-Montpetit, Montréal, Qc, H3T 1J4, Canada.
| | | | - Reza Jafari
- Optina Diagnostics, 3900 boul. Cote-Vertu, Suite #220, St-Laurent, Qc, H4R 1V4, Canada
| | - Susith Kulasekara
- University of Toronto, Department of Ophthalmology and Vision Sciences, Toronto Western Hospital, 399 Bathurst Street, Toronto, On, M5T 2S8, Canada
| | - Kalpana Rose
- University of Toronto, Department of Ophthalmology and Vision Sciences, Toronto Western Hospital, 399 Bathurst Street, Toronto, On, M5T 2S8, Canada
| | - Rachel Trussart
- Université de Montréal, Département d'ophtalmologie, 2900 Boulevard Édouard-Montpetit, Montréal, Qc, H3T 1J4, Canada
| | - Jean Daniel Arbour
- Université de Montréal, Département d'ophtalmologie, 2900 Boulevard Édouard-Montpetit, Montréal, Qc, H3T 1J4, Canada
| | - Chris Hudson
- University of Toronto, Department of Ophthalmology and Vision Sciences, Toronto Western Hospital, 399 Bathurst Street, Toronto, On, M5T 2S8, Canada; University of Waterloo, School of Optometry and Vision Science, 200 University Ave W, Waterloo, On, N2L 3G1, Canada
| | - Frédéric Lesage
- École Polytechnique de Montréal, Institut de génie biomédical, Département de Génie électrique, 2900, boul. Édouard-Montpetit, Montréal, Qc, H3T 1J4, Canada.
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18
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Blair NP, Wanek J, Teng PY, Shahidi M. The effect of intravitreal vascular endothelial growth factor on inner retinal oxygen delivery and metabolism in rats. Exp Eye Res 2015; 143:141-7. [PMID: 26518179 DOI: 10.1016/j.exer.2015.09.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Revised: 09/15/2015] [Accepted: 09/29/2015] [Indexed: 02/08/2023]
Abstract
Vascular endothelial growth factor (VEGF) is stimulated by hypoxia and plays an important role in pathologic vascular leakage and neovascularization. Increased VEGF may affect inner retinal oxygen delivery (DO2) and oxygen metabolism (MO2), however, quantitative information is lacking. We tested the hypotheses that VEGF increases DO2, but does not alter MO2. In 10 rats, VEGF was injected intravitreally into one eye, whereas balanced salt solution (BSS) was injected into the fellow eye, 24 h prior to imaging. Vessel diameters and blood velocities were determined by red-free and fluorescent microsphere imaging, respectively. Vascular PO2 values were derived by phosphorescence lifetime imaging of an intravascular oxyphor. Retinal blood flow, vascular oxygen content, DO2 and MO2 were calculated. Retinal arterial and venous diameters were larger in VEGF-injected eyes compared to control eyes (P < 0.03), however no significant difference was observed in blood velocity (P = 0.21). Thus, retinal blood flow was greater in VEGF-injected eyes (P = 0.007). Retinal vascular PO2 and oxygen content were similar between control and VEGF-injected eyes (P > 0.11), while the arteriovenous oxygen content difference was marginally lower in VEGF-injected eyes (P = 0.05). DO2 was 950 ± 340 and 1380 ± 650 nL O2/min in control and VEGF-injected eyes, respectively (P = 0.005). MO2 was 440 ± 150 and 490 ± 190 nL O2/min in control and VEGF-injected eyes, respectively (P = 0.31). Intravitreally administered VEGF did not alter MO2 but increased DO2, suggesting VEGF may play an offsetting role in conditions characterized by retinal hypoxia.
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Affiliation(s)
- Norman P Blair
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, 1855 West Taylor Street, Chicago, IL 60612, USA.
| | - Justin Wanek
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, 1855 West Taylor Street, Chicago, IL 60612, USA.
| | - Pang-yu Teng
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, 1855 West Taylor Street, Chicago, IL 60612, USA; UCLA Radiological Sciences, Suite 650, 924 Westwood Boulevard, Los Angeles, CA 90024, USA.
| | - Mahnaz Shahidi
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, 1855 West Taylor Street, Chicago, IL 60612, USA.
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Allen J, Howell K. Microvascular imaging: techniques and opportunities for clinical physiological measurements. Physiol Meas 2014; 35:R91-R141. [DOI: 10.1088/0967-3334/35/7/r91] [Citation(s) in RCA: 131] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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