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Lu Y, Hua Y, Wang B, Zhong F, Theophanous A, Tahir S, Lee PY, Sigal IA. The Robust Lamina Cribrosa Vasculature: Perfusion and Oxygenation Under Elevated Intraocular Pressure. Invest Ophthalmol Vis Sci 2024; 65:1. [PMID: 38691092 PMCID: PMC11077910 DOI: 10.1167/iovs.65.5.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Accepted: 03/21/2024] [Indexed: 05/03/2024] Open
Abstract
Purpose Elevated intraocular pressure (IOP) is thought to cause lamina cribrosa (LC) blood vessel distortions and potentially collapse, adversely affecting LC hemodynamics, reducing oxygenation, and triggering, or contributing to, glaucomatous neuropathy. We assessed the robustness of LC perfusion and oxygenation to vessel collapses. Methods From histology, we reconstructed three-dimensional eye-specific LC vessel networks of two healthy monkey eyes. We used numerical simulations to estimate LC perfusion and from this the oxygenation. We then evaluated the effects of collapsing a fraction of LC vessels (0%-36%). The collapsed vessels were selected through three scenarios: stochastic (collapse randomly), systematic (collapse strictly by the magnitude of local experimentally determined IOP-induced compression), and mixed (a combination of stochastic and systematic). Results LC blood flow decreased linearly as vessels collapsed-faster for stochastic and mixed scenarios and slower for the systematic one. LC regions suffering severe hypoxia (oxygen <8 mm Hg) increased proportionally to the collapsed vessels in the systematic scenario. For the stochastic and mixed scenarios, severe hypoxia did not occur until 15% of vessels collapsed. Some LC regions had higher perfusion and oxygenation as vessels collapsed elsewhere. Some severely hypoxic regions maintained normal blood flow. Results were equivalent for both networks and patterns of experimental IOP-induced compression. Conclusions LC blood flow was sensitive to distributed vessel collapses (stochastic and mixed) and moderately vulnerable to clustered collapses (systematic). Conversely, LC oxygenation was robust to distributed vessel collapses and sensitive to clustered collapses. Locally normal flow does not imply adequate oxygenation. The actual nature of IOP-induced vessel collapse remains unknown.
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Affiliation(s)
- Yuankai Lu
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Yi Hua
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
- Department of Biomedical Engineering, University of Mississippi, Mississippi, United States
- Department of Mechanical Engineering, University of Mississippi, Mississippi, United States
| | - Bingrui Wang
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Fuqiang Zhong
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Andrew Theophanous
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Shaharoz Tahir
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Po-Yi Lee
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Ian A. Sigal
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
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Ramesh PV, Morya AK, Aradhya AK, Pannerselvam P, Gopalakrishnan ST, Ramesh SV, Devadas AK, Krishna N. Unveiling the silent link: Normal-tension glaucoma's enigmatic bond with cardiac blood flow. World J Cardiol 2024; 16:10-15. [PMID: 38313391 PMCID: PMC10835469 DOI: 10.4330/wjc.v16.i1.10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Revised: 12/14/2023] [Accepted: 01/03/2024] [Indexed: 01/19/2024] Open
Abstract
This comprehensive review embarks on a captivating journey into the complex relationship between cardiology and normal-tension glaucoma (NTG), a condition that continues to baffle clinicians and researchers alike. NTG, characterized by optic nerve damage and visual field loss despite normal intraocular pressure, has long puzzled clinicians. One emerging perspective suggests that alterations in ocular blood flow, particularly within the optic nerve head, may play a pivotal role in its pathogenesis. While NTG shares commonalities with its high-tension counterpart, its unique pathogenesis and potential ties to cardiovascular health make it a fascinating subject of exploration. It navigates through the complex web of vascular dysregulation, blood pressure and perfusion pressure, neurovascular coupling, and oxidative stress, seeking to uncover the hidden threads that tie the heart and eyes together in NTG. This review explores into the intricate mechanisms connecting cardiovascular factors to NTG, shedding light on how cardiac dynamics can influence ocular health, particularly in cases where intraocular pressure remains within the normal range. NTG's enigmatic nature, often characterized by seemingly contradictory risk factors and clinical profiles, underscores the need for a holistic approach to patient care. Drawing parallels to cardiac health, we examine into the shared vascular terrain connecting the heart and the eyes. Cardiovascular factors, including systemic blood flow, endothelial dysfunction, and microcirculatory anomalies, may exert a profound influence on ocular perfusion, impacting the delicate balance within the optic nerve head. By elucidating the subtle clues and potential associations between cardiology and NTG, this review invites clinicians to consider a broader perspective in their evaluation and management of this elusive condition. As the understanding of these connections evolves, so too may the prospects for early diagnosis and tailored interventions, ultimately enhancing the quality of life for those living with NTG.
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Affiliation(s)
- Prasanna Venkatesh Ramesh
- Department of Glaucoma and Research, Mahathma Eye Hospital Private Limited, Trichy 620017, Tamil Nadu, India.
| | - Arvind Kumar Morya
- Department of Ophthalmology, All India Institute of Medical Sciences, Hyderabad 508126, Telangana, India
| | - Ajanya K Aradhya
- Department of Optometry and Visual Science, Mahathma Eye Hospital Private Limited, Trichy 620017, Tamil Nadu, India
| | | | | | - Shruthy Vaishali Ramesh
- Department of Cataract and Refractive Surgery, Mahathma Eye Hospital Private Limited, Trichy 620017, Tamil Nadu, India
| | - Aji Kunnath Devadas
- Department of Optometry and Visual Science, Mahathma Eye Hospital Private Limited, Trichy 620017, Tamil Nadu, India
| | - Navaneeth Krishna
- Department of Optometry and Visual Science, Mahathma Eye Hospital Private Limited, Trichy 620017, Tamil Nadu, India
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Nomura T, Yoshida T, Ito T, Ohno-Matsui K. Temporal Protrusion of the Optic Disc Implicated in Central Visual Field Abnormalities in High Myopia: Two Case Reports. Case Rep Ophthalmol 2024; 15:335-342. [PMID: 38623407 PMCID: PMC11018332 DOI: 10.1159/000538440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Accepted: 03/16/2024] [Indexed: 04/17/2024] Open
Abstract
Introduction Severe central visual field defects are frequently observed in highly myopic eyes. This report details 2 cases of central visual field defects in individuals with high myopia, characterized by an unusual temporal protrusion of the optic disc, a feature not previously documented. Case Presentation Two patients, a 54-year-old man and a 65-year-old woman, were diagnosed with high myopia in their left eyes, displaying an outward protrusion of the optic disc toward the macula. Swept-source optical coherence tomography revealed a focal lamina cribrosa defect at the temporal edge of the protruding optic disc, corresponding to the papillomacular bundle area of retinal nerve fibers, which exhibited thinning around the focal lamina cribrosa defect. Visual field examination indicated a central visual field defect in the affected eyes, which pattern corresponded to the papillomacular bundle responsible area. Conclusion The emergence of a temporal protrusion in the optic disc may lead to a focal lamina cribrosa defect, resulting in a central visual field defect in highly myopic eyes. This distinctive optic disc feature may constitute a critical risk factor for a central visual field defect. Hence, optic disc protrusion in high myopia warrants attention, necessitating careful ophthalmic examinations for central visual field defects.
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Affiliation(s)
- Takuhei Nomura
- Department of Ophthalmology and Visual Science, Tokyo Medical and Dental University, Tokyo, Japan
- Department of Ophthalmology, National Hospital Organization Disaster Medical Center, Tokyo, Japan
| | - Takeshi Yoshida
- Department of Ophthalmology and Visual Science, Tokyo Medical and Dental University, Tokyo, Japan
- Department of Advanced Ophthalmic Imaging Joint Research, Tokyo Medical and Dental University, Tokyo, Japan
| | - Taiju Ito
- Department of Ophthalmology and Visual Science, Tokyo Medical and Dental University, Tokyo, Japan
| | - Kyoko Ohno-Matsui
- Department of Ophthalmology and Visual Science, Tokyo Medical and Dental University, Tokyo, Japan
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Alasbali T. Current State of Knowledge in Ocular Blood Flow in Glaucoma: A Narrative Review. Clin Ophthalmol 2023; 17:2599-2607. [PMID: 37671333 PMCID: PMC10476666 DOI: 10.2147/opth.s426709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Accepted: 08/24/2023] [Indexed: 09/07/2023] Open
Abstract
Glaucoma is a multifactorial disease that is dependent on Intra Ocular Pressure (IOP) and associated with risk factors related to reduced ocular blood flow (OBF). In clinical practice, it is instrumental to update and review the considerable evidence of the current imaging technologies utilized in the investigation of OBF involved in both the onset and progression of glaucoma. Bibliographic databases, including PubMed and Google Scholar, were searched for articles on OBF techniques published between 2018 and 2023 using keywords such as "ocular blood flow", "glaucoma", "invasive ocular blood flow measurement", and "non-invasive ocular blood flow measurement". All types of methodologies were considered, except for editorials, letters to the editor, and animal studies. This review provides comprehensive information on the recent state-of-the-art imaging innovations used to monitor and measure the ocular blood flow in glaucoma.
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Affiliation(s)
- Tariq Alasbali
- Department of Ophthalmology, Faculty of Medicine, College of Medicine, Imam Mohammed Ibn Saud Islamic University, Riyadh, Saudi Arabia
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Banou L, Dastiridou A, Giannoukas A, Kouvelos G, Baros C, Androudi S. The Role of Color Doppler Imaging in the Diagnosis of Glaucoma: A Review of the Literature. Diagnostics (Basel) 2023; 13:diagnostics13040588. [PMID: 36832076 PMCID: PMC9954817 DOI: 10.3390/diagnostics13040588] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 01/31/2023] [Accepted: 02/02/2023] [Indexed: 02/08/2023] Open
Abstract
Glaucoma is a progressive optic neuropathy and one of the leading causes of irreversible blindness worldwide. Elevated intraocular pressure (IOP) is the major risk factor for the onset and progression of glaucoma. In addition to elevated IOP, impaired intraocular blood flow is also considered to be involved in the pathogenesis of glaucoma. Various techniques have been used to assess ocular blood flow (OBF), including Color Doppler Imaging (CDI), a technique used in ophthalmology in recent decades. This article reviews the role of CDI in both the diagnosis and effective monitoring of glaucoma progression, presenting the protocol for imaging and its advantages, as well as the limitations of its use. Moreover, it analyzes the pathophysiology of glaucoma, focusing on vascular theory and its role in the onset and progression of the disease.
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Affiliation(s)
- Lamprini Banou
- Department of Ophthalmology, University of Thessaly, 41334 Larissa, Greece
| | - Anna Dastiridou
- Department of Ophthalmology, University of Thessaly, 41334 Larissa, Greece
- Correspondence:
| | | | - Georgios Kouvelos
- Department of Vascular Surgery, University of Thessaly, 41334 Larissa, Greece
| | - Christos Baros
- Department of Vascular Surgery, University of Thessaly, 41334 Larissa, Greece
| | - Sofia Androudi
- Department of Ophthalmology, University of Thessaly, 41334 Larissa, Greece
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Suzuki Y, Kiyosawa M. Cardiac Hypertrophy May Be a Risk Factor for the Development and Severity of Glaucoma. Biomedicines 2022; 10:biomedicines10030677. [PMID: 35327479 PMCID: PMC8945816 DOI: 10.3390/biomedicines10030677] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2022] [Revised: 03/09/2022] [Accepted: 03/13/2022] [Indexed: 02/05/2023] Open
Abstract
The purpose of this study was to examine the relationship between glaucoma and cardiac abnormalities. We evaluated 581 patients with open-angle glaucoma (285 men and 296 women) and 595 individuals without glaucoma (273 men and 322 women). All of the participants underwent visual field testing using a Humphrey Visual Field Analyzer (30-2 program), an electrocardiogram (ECG), and blood pressure measurement. We examined the ECG abnormalities and other factors (age, intraocular pressure (IOP) and systemic hypertension) involved in the development and severity of glaucoma. Logistic regression analyses revealed significant correlations of glaucoma with IOP (OR = 1.43; 95% CI: 1.36−1.51; p < 0.00001), atrial fibrillation (OR = 2.02; 95% CI: 1.01−4.04; p = 0.04), left ventricular hypertrophy (LVH) (OR = 2.21; 95% CI: 1.15−4.25; p = 0.02), and bradycardia (OR = 2.19; 95% CI: 1.25−4.70; p = 0.02). Regression analyses revealed significant correlations of the mean deviation of the visual field with age (t = −6.22; 95% CI: −0.15, −0.08; p < 0.00001), IOP (t = −6.47; 95% CI: −0.42, −0.23; p < 0.00001), and LVH (t = −2.15; 95% CI: −3.36, −0.29; p = 0.02). Atrial fibrillation, LVH and bradycardia may decrease the cerebral blood flow, and may also affect the ocular blood flow. Cardiac abnormalities may be associated with the development and severity of glaucoma.
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Affiliation(s)
- Yukihisa Suzuki
- Department of Ophthalmology, Japan Community Health Care Organization, Mishima General Hospital, Shizuoka 411-0801, Japan
- Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, Tokyo 173-0015, Japan
- Correspondence: ; Tel.: +81-55-975-3031; Fax: +81-55-973-3647
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