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Yuan Y, Dong M, Wen S, Yuan X, Zhou L. Retinal microcirculation: A window into systemic circulation and metabolic disease. Exp Eye Res 2024; 242:109885. [PMID: 38574944 DOI: 10.1016/j.exer.2024.109885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 04/01/2024] [Accepted: 04/02/2024] [Indexed: 04/06/2024]
Abstract
The retinal microcirculation system constitutes a unique terminal vessel bed of the systemic circulation, and its perfusion status is directly associated with the neural function of the retina. This vascular network, essential for nourishing various layers of the retina, comprises two primary microcirculation systems: the retinal microcirculation and the choroidal microcirculation, with each system supplying blood to distinct retinal layers and maintaining the associated neural function. The blood flow of those capillaries is regulated via different mechanisms. However, a range of internal and external factors can disrupt the normal architecture and blood flow within the retinal microcirculation, leading to several retinal pathologies, including diabetic retinopathy, macular edema, and vascular occlusions. Metabolic disturbances such as hyperglycemia, hypertension, and dyslipidemia are known to modify retinal microcirculation through various pathways. These alterations are observable in chronic metabolic conditions like diabetes, coronary artery disease, and cerebral microvascular disease due to advances in non-invasive or minimally invasive retinal imaging techniques. Thus, examination of the retinal microcirculation can provide insights into the progression of numerous chronic metabolic disorders. This review discusses the anatomy, physiology and pathophysiology of the retinal microvascular system, with a particular emphasis on the connections between retinal microcirculation and systemic circulation in both healthy states and in the context of prevalent chronic metabolic diseases.
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Affiliation(s)
- Yue Yuan
- Department of Endocrinology, Shanghai Pudong Hospital, Fudan University, Shanghai, 201399, China.
| | - Meiyuan Dong
- Department of Endocrinology, Shanghai Pudong Hospital, Fudan University, Shanghai, 201399, China; Graduate School of Hebei Medical University, Shijiazhuang, China.
| | - Song Wen
- Department of Endocrinology, Shanghai Pudong Hospital, Fudan University, Shanghai, 201399, China.
| | - Xinlu Yuan
- Department of Endocrinology, Shanghai Pudong Hospital, Fudan University, Shanghai, 201399, China.
| | - Ligang Zhou
- Department of Endocrinology, Shanghai Pudong Hospital, Fudan University, Shanghai, 201399, China; Graduate School of Hebei Medical University, Shijiazhuang, China; Shanghai Key Laboratory of Vascular Lesions Regulation and Remodeling, Shanghai Pudong Hospital, Shanghai, China.
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Cohen-Sinai N, Man-Peles I, Zahavi A, Luckman J, Goldenberg-Cohen N. Simplifying the diagnosis of optic tract lesions. Front Med (Lausanne) 2022; 9:1029829. [DOI: 10.3389/fmed.2022.1029829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2022] [Accepted: 10/10/2022] [Indexed: 11/13/2022] Open
Abstract
Optic tract lesions (OTL) are often difficult to diagnose. We suggest an algorithm to simplify the often-challenging diagnosis of OTL. Clinical and imaging data were retrospectively collected from the electronic files of 6 patients diagnosed with OTL at a tertiary medical center in 2016–2020. The series included 4 children and 2 adults with an OTL caused by a glioma (n = 5) or motor vehicle accident (n = 1). Magnetic resonance imaging (MRI) revealed a suprasellar glioma involving the chiasm and tract alone (n = 1) and the ipsilateral optic nerve (n = 2) and only optic tract (3). Perimetry showed incongruent homonymous hemianopia in 3 patients. In two patients, perimetry could only be performed in one eye, and demonstrated hemianopia. In one patient perimetry was unreliable. Fundus examination revealed bow-tie atrophy in all patients. On optical coherence tomography (OCT) of the peripapillary retinal nerve fiber layer (RNFL) horizontal thinning was observed in the contralateral eye (n = 6). By presenting the information in a predefined order—visual field damage, OCT RNFL thickness, and MRI—the diagnosis could be easily reached even in children, and when other structures like the chiasm were involved. Fundus photographs easily detect bow tie atrophy in children. Systematic presentation of the data in a predefined order can ease the diagnostic process of OTLs.
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Badawi SA, Fraz MM, Shehzad M, Mahmood I, Javed S, Mosalam E, Nileshwar AK. Detection and Grading of Hypertensive Retinopathy Using Vessels Tortuosity and Arteriovenous Ratio. J Digit Imaging 2022; 35:281-301. [PMID: 35013827 PMCID: PMC8921404 DOI: 10.1007/s10278-021-00545-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 11/09/2021] [Accepted: 11/11/2021] [Indexed: 10/19/2022] Open
Abstract
Hypertensive retinopathy (HR) refers to changes in the morphological diameter of the retinal vessels due to persistent high blood pressure. Early detection of such changes helps in preventing blindness or even death due to stroke. These changes can be quantified by computing the arteriovenous ratio and the tortuosity severity in the retinal vasculature. This paper presents a decision support system for detecting and grading HR using morphometric analysis of retinal vasculature, particularly measuring the arteriovenous ratio (AVR) and retinal vessel tortuosity. In the first step, the retinal blood vessels are segmented and classified as arteries and veins. Then, the width of arteries and veins is measured within the region of interest around the optic disk. Next, a new iterative method is proposed to compute the AVR from the caliber measurements of arteries and veins using Parr-Hubbard and Knudtson methods. Moreover, the retinal vessel tortuosity severity index is computed for each image using 14 tortuosity severity metrics. In the end, a hybrid decision support system is proposed for the detection and grading of HR using AVR and tortuosity severity index. Furthermore, we present a new publicly available retinal vessel morphometry (RVM) dataset to evaluate the proposed methodology. The RVM dataset contains 504 retinal images with pixel-level annotations for vessel segmentation, artery/vein classification, and optic disk localization. The image-level labels for vessel tortuosity index and HR grade are also available. The proposed methods of iterative AVR measurement, tortuosity index, and HR grading are evaluated using the new RVM dataset. The results indicate that the proposed method gives superior performance than existing methods. The presented methodology is a novel advancement in automated detection and grading of HR, which can potentially be used as a clinical decision support system.
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Affiliation(s)
- Sufian A Badawi
- School of Electrical Engineering and Computer Science, National University of Sciences and Technology (NUST), Islamabad, Pakistan
| | - Muhammad Moazam Fraz
- School of Electrical Engineering and Computer Science, National University of Sciences and Technology (NUST), Islamabad, Pakistan.
| | - Muhammad Shehzad
- School of Electrical Engineering and Computer Science, National University of Sciences and Technology (NUST), Islamabad, Pakistan
| | - Imran Mahmood
- School of Electrical Engineering and Computer Science, National University of Sciences and Technology (NUST), Islamabad, Pakistan
| | - Sajid Javed
- Department of Electrical Engineering and Computer Science, Khalifa University, Abu Dhabi, UAE
| | - Emad Mosalam
- Department of Ophthalmology, RAK Medical and Health Sciences University, Ras Al Khaimah, UAE.,Department of Ophthalmology, Saqr Hospital, Ministry of Health and Prevention, Ras Al Khaimah, UAE
| | - Ajay Kamath Nileshwar
- Department of Ophthalmology, RAK Medical and Health Sciences University, Ras Al Khaimah, UAE.,Department of Ophthalmology, Saqr Hospital, Ministry of Health and Prevention, Ras Al Khaimah, UAE
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Abstract
PURPOSE OF REVIEW The retina is growingly recognized as a window into cerebrovascular and systemic vascular conditions. The utility of noninvasive retinal vessel biomarkers in cerebrovascular risk assessment has expanded due to advances in retinal imaging techniques and machine learning-based digital analysis. The purpose of this review is to underscore the latest evidence linking retinal vascular abnormalities with stroke and vascular-related cognitive disorders; to highlight modern developments in retinal vascular imaging modalities and software-based vasculopathy quantification. RECENT FINDINGS Longitudinal studies undertaken for extended periods indicate that retinal vascular changes can predict cerebrovascular disorders (CVD). Cerebrovascular ties to dementia provoked recent explorations of retinal vessel imaging tools for conceivable early cognitive decline detection. Innovative biomedical engineering technologies and advanced dynamic and functional retinal vascular imaging methods have recently been added to the armamentarium, allowing an unbiased and comprehensive analysis of the retinal vasculature. Improved artificial intelligence-based deep learning algorithms have boosted the application of retinal imaging as a clinical and research tool to screen, risk stratify, and monitor with precision CVD and vascular cognitive impairment. SUMMARY Mounting evidence supports the use of quantitative retinal vessel analysis in predicting CVD, from clinical stroke to neuroimaging markers of stroke and neurodegeneration.
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Cao Y, Yan J, Zhan Z, Liang Y, Han Z. Macula Structure and Microvascular Changes in Recent Small Subcortical Infarct Patients. Front Neurol 2021; 11:615252. [PMID: 33488504 PMCID: PMC7817655 DOI: 10.3389/fneur.2020.615252] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Accepted: 11/23/2020] [Indexed: 12/29/2022] Open
Abstract
Purpose: This study aimed to assess the macula structure and capillaries in the macula and optic nerve head in recent small subcortical infarct (RSSI) patients. Methods: This observational cross-sectional study included 40 RSSI patients and 46 healthy controls. Optical coherence tomography angiography was used to image the capillaries in the macula and optic nerve head. An inbuilt algorithm was used to measure the densities in the microvasculature of the macula [superficial retinal capillary plexus (SRCP) and deep retinal capillary plexus (DRCP)] and optic nerve head [radial peripapillary capillary (RPC)] and thickness around the optic nerve head, peripapillary retinal nerve fiber layer (pRNFL). Results: Densities in RPC (P < 0.001), SRCP (P = 0.001), and DRCP (P = 0.003) were reduced in RSSI patients when compared with healthy controls. The pRNFL thickness was thinner (P < 0.001) in RSSI patients than healthy controls. In the RSSI group, the SRCP density significantly correlated with the DRCP density (rho = 0.381, P = 0.042). The pRNFL thickness displayed a significant relationship with the RPC density (rho = 0.482, P = 0.003) in the RSSI group. Conclusions: RSSI patients showed interrupted capillary plexuses leading to its significant impairment and neurodegeneration. Our report provides insight into the macula capillary microcirculation changes in RSSI.
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Affiliation(s)
- Yungang Cao
- Department of Neurology, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, China
| | - Jueyue Yan
- School of Medicine, First Affiliated Hospital, Zhejiang University, Hangzhou, China
| | - Zhenxiang Zhan
- Department of Neurology, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, China
| | - Yuanbo Liang
- Eye Hospital of Wenzhou Medical University, Wenzhou, China
| | - Zhao Han
- Department of Neurology, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, China
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Safadi K, Kruger JM, Chowers I, Solomon A, Amer R, Aweidah H, Frenkel S, Mechoulam H, Anteby I, Ben Eli H, Lavy I, Jaouni T, Landau D, Tiosano L, Greifner G, Ofir S, Levi Vineberg T, Levy J. Ophthalmology practice during the COVID-19 pandemic. BMJ Open Ophthalmol 2020; 5:e000487. [PMID: 32432169 PMCID: PMC7222613 DOI: 10.1136/bmjophth-2020-000487] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 04/08/2020] [Indexed: 12/22/2022] Open
Abstract
OBJECTIVE To present an established practice protocol for safe and effective hospital-setting ophthalmic practice during the coronavirus disease 2019 (COVID-19) pandemic. METHODS AND ANALYSIS Literature was reviewed to identify articles relevant to COVID-19 pandemic and ophthalmology. The following keywords were used: COVID-19, SARS-CoV-2 and telemedicine, combined with eye, ophthalmology, conjunctivitis and tears. Data were extracted from the identified manuscripts and discussed among subspecialists to obtain consensus evidence-based practice. RESULTS A protocol for ophthalmic practice in the era of COVID-19 pandemic was established. The protocol covered patient screening, clinic flow, required personal protective equipment and modifications of ophthalmic equipment for improved safety. CONCLUSION Important literature emerged with respect to the practice of ophthalmology in the era of COVID-19. An evidence-based ophthalmic practice protocol was established and should be modified in the future to accommodate new insights on the COVID-19 pandemic.
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Affiliation(s)
- Khaled Safadi
- Ophthalmology Department, Hadassah Medical Center, Jerusalem, Israel
| | - Joshua M Kruger
- Ophthalmology Department, Hadassah Medical Center, Jerusalem, Israel
| | - Itay Chowers
- Ophthalmology Department, Hadassah Medical Center, Jerusalem, Israel
| | - Abraham Solomon
- Ophthalmology Department, Hadassah Medical Center, Jerusalem, Israel
| | - Radgonde Amer
- Ophthalmology Department, Hadassah Medical Center, Jerusalem, Israel
| | - Hamzah Aweidah
- Ophthalmology Department, Hadassah Medical Center, Jerusalem, Israel
| | - Shahar Frenkel
- Ophthalmology Department, Hadassah Medical Center, Jerusalem, Israel
| | - Hadas Mechoulam
- Ophthalmology Department, Hadassah Medical Center, Jerusalem, Israel
| | - Irene Anteby
- Ophthalmology Department, Hadassah Medical Center, Jerusalem, Israel
| | - Hadas Ben Eli
- Ophthalmology Department, Hadassah Medical Center, Jerusalem, Israel
| | - Itay Lavy
- Ophthalmology Department, Hadassah Medical Center, Jerusalem, Israel
| | - Tarek Jaouni
- Ophthalmology Department, Hadassah Medical Center, Jerusalem, Israel
| | - David Landau
- Ophthalmology Department, Hadassah Medical Center, Jerusalem, Israel
| | - Liran Tiosano
- Ophthalmology Department, Hadassah Medical Center, Jerusalem, Israel
| | - Gabriel Greifner
- Ophthalmology Department, Hadassah Medical Center, Jerusalem, Israel
| | - Shay Ofir
- Ophthalmology Department, Hadassah Medical Center, Jerusalem, Israel
| | | | - Jaime Levy
- Ophthalmology Department, Hadassah Medical Center, Jerusalem, Israel
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Fatehi F, Jahedi F, Tay-Kearney ML, Kanagasingam Y. Teleophthalmology for the elderly population: A review of the literature. Int J Med Inform 2020; 136:104089. [DOI: 10.1016/j.ijmedinf.2020.104089] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2019] [Revised: 12/13/2019] [Accepted: 01/27/2020] [Indexed: 11/30/2022]
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Abstract
PURPOSE OF REVIEW The funduscopic examination can be a technically difficult, and often omitted, portion of the neurologic examination, despite its great potential to influence patient care. RECENT FINDINGS Medical practitioners are often first taught to examine the ocular fundus using a direct ophthalmoscope, however, this skill requires frequent practice. Nonmydriatic tabletop and portable fundus photography and even smartphone-based photography offer alternative and practical means for approaching examination of the ocular fundus. These alternative tools have been shown to be practical in a variety of settings including ambulatory clinics and emergency departments. Decreased retinal microvascular density detected with fundus photography has been linked to accelerated rates of cognitive decline. Research has also found optic disc pallor and retinopathy detected via fundus photography to be more prevalent in patients with recent stroke or transient ischemic attack. SUMMARY Alternative methods of funduscopic examination based on fundus photography have the potential to improve the ease of use, portability, and availability of funduscopy. Recognition of changes in retinal microvasculature has the potential to noninvasively identify patients at the highest risk for cognitive impairment and cerebrovascular disease. However, further research is needed to determine the specific utility of measurements of retinal microvascular changes in clinical care. Innovative funduscopy techniques offer neurologists new approaches to this essential facet of the neurological examination.
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Sprödhuber A, Wolz J, Budai A, Laumeier I, Audebert HJ, Michelson G. The Role of Retinal Vascular Density as a Screening Tool for Ageing and Stroke. Ophthalmic Res 2018; 60:1-8. [PMID: 29874669 DOI: 10.1159/000488491] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 03/14/2018] [Indexed: 11/19/2022]
Abstract
OBJECTIVES To measure the density of retinal vessels from digitized fundus photographs in patients with recent stroke and age-matched controls. To investigate whether the parameter retinal vascular density (RVD) served as a quantitative marker for cerebrovascular events. METHODS Digitized fundus photographs of n = 158 subjects with stroke or transient ischemic attack within 1 year at the time of examination and n = 1,250 age-matched controls without any remarkable medical history were examined. Sex, hypertension, and diabetes were considered to be cofactors. Measurement of RVD was performed with a computer-aided image-analyzing program by segmenting automatically all visible retinal vessels and measuring areas of vessels in distinct circles around the optic disk. RESULTS In controls RVD dwindles with increasing distance from the optic disk. RVD decreased significantly with age (p = 0.000). Stroke patients showed significantly lower values of RVD of -15% in comparison to age-matched controls. In old subjects, stroke in combination with hypertension is associated with a significant decreased RVD, and in middle-aged subjects diabetes and stroke are associated with a significant decreased RVD (p = 0.01). CONCLUSION Age and stroke are significant risk factors for decreased RVD. Diabetes and arterial hypertension are additional significant risk factors in patients with stroke with respect to RVD.
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Affiliation(s)
- Andrea Sprödhuber
- Department of Ophthalmology, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Johannes Wolz
- Department of Ophthalmology, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Attila Budai
- Pattern Recognition Lab and Graduate School in Advanced Optical Technologies, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
| | - Inga Laumeier
- Center for Stroke Research Berlin, Department of Neurology, Charité Berlin, Berlin, Germany
| | - Heinrich J Audebert
- Center for Stroke Research Berlin, Department of Neurology, Charité Berlin, Berlin, Germany
| | - Georg Michelson
- Department of Ophthalmology, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erlangen, Germany.,Interdisciplinary Center of Ophthalmic Preventive Medicine and Imaging, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erlangen, Germany.,Talkingeyes & More GmbH, Medical Valley Center, Erlangen, Germany
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Cabrera DeBuc D, Somfai GM, Koller A. Retinal microvascular network alterations: potential biomarkers of cerebrovascular and neural diseases. Am J Physiol Heart Circ Physiol 2016; 312:H201-H212. [PMID: 27923786 DOI: 10.1152/ajpheart.00201.2016] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Revised: 11/04/2016] [Accepted: 11/11/2016] [Indexed: 12/12/2022]
Abstract
Increasing evidence suggests that the conditions of retinal microvessels are indicators to a variety of cerebrovascular, neurodegenerative, psychiatric, and developmental diseases. Thus noninvasive visualization of the human retinal microcirculation offers an exceptional opportunity for the investigation of not only the retinal but also cerebral microvasculature. In this review, we show how the conditions of the retinal microvessels could be used to assess the conditions of brain microvessels because the microvascular network of the retina and brain share, in many aspects, standard features in development, morphology, function, and pathophysiology. Recent techniques and imaging modalities, such as optical coherence tomography (OCT), allow more precise visualization of various layers of the retina and its microcirculation, providing a "microscope" to brain microvessels. We also review the potential role of retinal microvessels in the risk identification of cerebrovascular and neurodegenerative diseases. The association between vision problems and cerebrovascular and neurodegenerative diseases, as well as the possible role of retinal microvascular imaging biomarkers in cerebrovascular and neurodegenerative screening, their potentials, and limitations, are also discussed.
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Affiliation(s)
- Delia Cabrera DeBuc
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida;
| | - Gabor Mark Somfai
- Semmelweis University, Budapest, Hungary.,Augenzentrum, Pallas Kliniken, Olten, Switzerland
| | - Akos Koller
- Institute of Natural Sciences, University of Physical Education, Budapest, Hungary; and.,Department of Physiology, New York Medical College, Valhalla, New York
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