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Burma JS, Roy MA, Kennedy CM, Labrecque L, Brassard P, Smirl JD. A systematic review, meta-analysis and meta-regression amalgamating the driven approaches used to quantify dynamic cerebral autoregulation. J Cereb Blood Flow Metab 2024; 44:1271-1297. [PMID: 38635887 PMCID: PMC11342731 DOI: 10.1177/0271678x241235878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 12/29/2023] [Accepted: 01/16/2024] [Indexed: 04/20/2024]
Abstract
Numerous driven techniques have been utilized to assess dynamic cerebral autoregulation (dCA) in healthy and clinical populations. The current review aimed to amalgamate this literature and provide recommendations to create greater standardization for future research. The PubMed database was searched with inclusion criteria consisting of original research articles using driven dCA assessments in humans. Risk of bias were completed using Scottish Intercollegiate Guidelines Network and Methodological Index for Non-Randomized Studies. Meta-analyses were conducted for coherence, phase, and gain metrics at 0.05 and 0.10 Hz using deep-breathing, oscillatory lower body negative pressure (OLBNP), sit-to-stand maneuvers, and squat-stand maneuvers. A total of 113 studies were included, with 40 of these incorporating clinical populations. A total of 4126 participants were identified, with younger adults (18-40 years) being the most studied population. The most common techniques were squat-stands (n = 43), deep-breathing (n = 25), OLBNP (n = 20), and sit-to-stands (n = 16). Pooled coherence point estimates were: OLBNP 0.70 (95%CI:0.59-0.82), sit-to-stands 0.87 (95%CI:0.79-0.95), and squat-stands 0.98 (95%CI:0.98-0.99) at 0.05 Hz; and deep-breathing 0.90 (95%CI:0.81-0.99); OLBNP 0.67 (95%CI:0.44-0.90); and squat-stands 0.99 (95%CI:0.99-0.99) at 0.10 Hz. This review summarizes clinical findings, discusses the pros/cons of the 11 unique driven techniques included, and provides recommendations for future investigations into the unique physiological intricacies of dCA.
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Affiliation(s)
- Joel S Burma
- Cerebrovascular Concussion Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Canada
- Sport Injury Prevention Research Centre, Faculty of Kinesiology, University of Calgary, Calgary, Canada
- Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Canada
- Hotchkiss Brain Institute, University of Calgary, Calgary, Canada
- Integrated Concussion Research Program, University of Calgary, Calgary, Canada
- Alberta Children’s Hospital Research Institute, University of Calgary, Calgary, Canada
- Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Canada
| | - Marc-Antoine Roy
- Department of Kinesiology, Faculty of Medicine, Université Laval, Québec, Canada
- Research Center of the Institut Universitaire de Cardiologie et de Pneumologie de Québec, Québec, Canada
| | - Courtney M Kennedy
- Cerebrovascular Concussion Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Canada
- Sport Injury Prevention Research Centre, Faculty of Kinesiology, University of Calgary, Calgary, Canada
- Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Canada
- Hotchkiss Brain Institute, University of Calgary, Calgary, Canada
- Integrated Concussion Research Program, University of Calgary, Calgary, Canada
- Alberta Children’s Hospital Research Institute, University of Calgary, Calgary, Canada
- Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Canada
| | - Lawrence Labrecque
- Department of Kinesiology, Faculty of Medicine, Université Laval, Québec, Canada
- Research Center of the Institut Universitaire de Cardiologie et de Pneumologie de Québec, Québec, Canada
| | - Patrice Brassard
- Department of Kinesiology, Faculty of Medicine, Université Laval, Québec, Canada
- Research Center of the Institut Universitaire de Cardiologie et de Pneumologie de Québec, Québec, Canada
| | - Jonathan D Smirl
- Cerebrovascular Concussion Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Canada
- Sport Injury Prevention Research Centre, Faculty of Kinesiology, University of Calgary, Calgary, Canada
- Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Canada
- Hotchkiss Brain Institute, University of Calgary, Calgary, Canada
- Integrated Concussion Research Program, University of Calgary, Calgary, Canada
- Alberta Children’s Hospital Research Institute, University of Calgary, Calgary, Canada
- Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Canada
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Mravec Bencurova D, Vyborny P, Dankova P. Comparative analysis of tear cytokines in patients with glaucoma, ocular hypertension, and healthy controls. Int Ophthalmol 2023; 43:3559-3568. [PMID: 37318666 PMCID: PMC10504217 DOI: 10.1007/s10792-023-02763-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Accepted: 05/21/2023] [Indexed: 06/16/2023]
Abstract
PURPOSE To investigate the ocular surface inflammation in patients with primary open angle glaucoma and ocular hypertension by analyzing tears and to compare findings with healthy controls. METHODS Observational case-control study. Tear samples were collected by 5 µl microcapillary tube from 24 patients with glaucoma treated by antiglaucoma drops, 9 non-treated patients with ocular hypertension and 45 healthy controls. Tears were analyzed from right eye by multiplex Bio-Plex system for the presence of 6 cytokines: IL1β, IL10, IL4, IFNγ, MIF and VEGF. RESULTS Significantly higher concentrations of IL1β and IL10 (glaucoma or ocular hypertension vs. healthy controls, p < 0.0001), VEGF (glaucoma vs. ocular hypertension, p < 0.05; ocular hypertension vs. healthy controls, p < 0.02) and MIF (glaucoma vs. healthy controls, p < 0.03) were detected in patients' tears. Both patient groups have activated to a significantly lower extent the Th1 pathway represented by IFNγ than Th2 pathway represented by IL10 (p < 0.001) and, at the same time, the IFNγ/IL4 ratio was significantly increased in healthy controls (p < 0.001) and patients with ocular hypertension (p < 0.02) compared to glaucoma individuals. CONCLUSION This study shows that secretion of inflammation-related cytokines by conjunctival cells is increased in both, glaucoma and ocular hypertension patients and can be detected in their tears. Nevertheless, data indicates stronger ocular surface inflammation in non-treated follow-up patients diagnosed with ocular hypertension than in glaucoma subjects treated by antiglaucoma drops.
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Affiliation(s)
- Dominika Mravec Bencurova
- Department of Anthropology and Human Genetics, Faculty of Science, Charles University, Viničná 7, 12843, Prague 2, Czech Republic
| | - Petr Vyborny
- Eye Department, 1-St Faculty of Medicine, Charles University and Central Military Hospital Prague, Prague 6, Czech Republic
| | - Pavlina Dankova
- Department of Anthropology and Human Genetics, Faculty of Science, Charles University, Viničná 7, 12843, Prague 2, Czech Republic.
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Hsu E, Desai M. Glaucoma and Systemic Disease. Life (Basel) 2023; 13:life13041018. [PMID: 37109547 PMCID: PMC10143901 DOI: 10.3390/life13041018] [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: 03/23/2023] [Revised: 04/09/2023] [Accepted: 04/12/2023] [Indexed: 04/29/2023] Open
Abstract
Glaucoma is the leading cause of irreversible blindness in the world. Due to its potential to cause permanent vision loss, it is important to understand how systemic conditions and their respective treatments can be associated with or increase the risk for developing glaucoma. In this review, we examined the literature for up-to-date discussions and provided commentary on glaucoma, its pathophysiology, and associated risk factors. We discuss systemic diseases and the impact, risk, and mechanism for developing glaucoma, including pharmacologically induced glaucoma; inflammatory and auto-immune conditions; infectious, dermatologic, cardiovascular, pulmonary, renal, urologic, neurologic, psychiatric and systemic malignancies: intraocular tumors; as well as pediatric, and genetic conditions. The goal of our discussion of systemic conditions including their commonality, mechanisms, treatments, and associations with developing glaucoma is to emphasize the importance of ocular examinations and follow-up with the multidisciplinary teams involved in the care of each patient to prevent unnecessary vision-loss.
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Affiliation(s)
- Eugene Hsu
- Department of Ophthalmology, Boston University School of Medicine, 85 East Concord Street, 8th Floor, Boston, MA 02118, USA
| | - Manishi Desai
- Department of Ophthalmology, Boston University School of Medicine, 85 East Concord Street, 8th Floor, Boston, MA 02118, USA
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Mroczkowska S, Shokr H, Benavente-Pérez A, Negi A, Bentham P, Gherghel D. Retinal Microvascular Dysfunction Occurs Early and Similarly in Mild Alzheimer's Disease and Primary-Open Angle Glaucoma Patients. J Clin Med 2022; 11:6702. [PMID: 36431179 PMCID: PMC9717733 DOI: 10.3390/jcm11226702] [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: 09/29/2022] [Revised: 11/06/2022] [Accepted: 11/11/2022] [Indexed: 11/16/2022] Open
Abstract
Purpose: To assess the similarities and differences in retinal microvascular function between mild Alzheimer’s disease (AD) patients, early-stage primary open angle glaucoma (POAG) patients and healthy controls. Methods: Retinal vessel reactivity to flickering light was assessed in 10 AD, 19 POAG and 20 healthy age matched control patients by means of dynamic retinal vessel analysis (DVA, IMEDOS, GmbH, Jena, Germany) according to an established protocol. All patients additionally underwent BP measurements and blood analysis for glucose and lipid metabolism markers. Results: AD and POAG patients demonstrated comparable alterations in retinal artery reactivity, in the form of an increased arterial reaction time (RT) to flicker light on the final flicker cycle (p = 0.009), which was not replicated by healthy controls (p > 0.05). Furthermore, the sequential changes in RT on progressing from flicker one to flicker three were found to differ between healthy controls and the two disease groups (p = 0.001). Conclusion: AD and POAG patients demonstrate comparable signs of vascular dysfunction in their retinal arteries at the early stages of their disease process. This provides support for the concept of a common underlying vascular aetiology in these two neurodegenerative diseases.
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Affiliation(s)
- Stephanie Mroczkowska
- Vascular Research Laboratory, Ophthalmic Research Group, College Health and Life Sciences, Aston University, Birmingham B4 7ET, UK
- Eye and Vision Research Group, School of Health Professions, Plymouth University, Plymouth PL4 8AA, UK
| | - Hala Shokr
- Vascular Research Laboratory, Ophthalmic Research Group, College Health and Life Sciences, Aston University, Birmingham B4 7ET, UK
- Pharmacy Division, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PL, UK
| | - Alexandra Benavente-Pérez
- Vascular Research Laboratory, Ophthalmic Research Group, College Health and Life Sciences, Aston University, Birmingham B4 7ET, UK
| | - Anil Negi
- Medical Innovation Development and Research Unit, University Hospitals Birmingham NHS Foundation Trust, Birmingham B15 1NT, UK
| | - Peter Bentham
- Medical Innovation Development and Research Unit, University Hospitals Birmingham NHS Foundation Trust, Birmingham B15 1NT, UK
| | - Doina Gherghel
- Vascular Research Laboratory, Ophthalmic Research Group, College Health and Life Sciences, Aston University, Birmingham B4 7ET, UK
- Division of Cardiovascular Sciences, University of Manchester, Manchester M13 9PL, UK
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Hamarat Y, Deimantavicius M, Dambrauskas V, Labunskas V, Putnynaite V, Lucinskas P, Siaudvytyte L, Simiene E, Stoskuviene A, Januleviciene I, Petkus V, Ragauskas A. Prospective Pilot Clinical Study of Noninvasive Cerebrovascular Autoregulation Monitoring in Open-Angle Glaucoma Patients and Healthy Subjects. Transl Vis Sci Technol 2022; 11:17. [PMID: 35138342 PMCID: PMC8842541 DOI: 10.1167/tvst.11.2.17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose To analyze the cerebrovascular autoregulation (CA) dynamics in patients with normal-tension glaucoma (NTG) and high-tension glaucoma (HTG) as well as healthy subjects using noninvasive ultrasound technologies for the first time. Methods The CA status of 10 patients with NTG, 8 patients with HTG, and 10 healthy subjects was assessed, using an innovative noninvasive ultrasonic technique, based on intracranial blood volume slow-wave measurements. Identified in each participant were intraocular pressure, ocular perfusion pressure, and CA-related parameter volumetric reactivity index (VRx), as well as the duration and doses of the longest cerebral autoregulation impairment (LCAI). In addition, we calculated the associations of these parameters with patients' diagnoses. Results The VRx value, the LCAI dose, and duration in healthy subjects were significantly lower than in patients with NTG (P < 0.05). However, no significant differences were noted in these parameters between healthy subjects and HTG and between NTG and HTG groups. Conclusions NTG is associated with the disturbed cerebral blood flow and could be diagnosed by performing noninvasive CA assessments. Translational Relevance The VRx monitoring method can be applied to a wider range of patient groups, especially patients with normal-tension glaucoma.
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Affiliation(s)
- Yasin Hamarat
- Health Telematics Science Institute, Kaunas University of Technology, Kaunas, Lithuania.,0000-0002-1343-5068
| | - Mantas Deimantavicius
- Health Telematics Science Institute, Kaunas University of Technology, Kaunas, Lithuania
| | - Vilius Dambrauskas
- Health Telematics Science Institute, Kaunas University of Technology, Kaunas, Lithuania
| | - Vaidas Labunskas
- Health Telematics Science Institute, Kaunas University of Technology, Kaunas, Lithuania
| | - Vilma Putnynaite
- Health Telematics Science Institute, Kaunas University of Technology, Kaunas, Lithuania
| | - Paulius Lucinskas
- Health Telematics Science Institute, Kaunas University of Technology, Kaunas, Lithuania
| | - Lina Siaudvytyte
- Eye Clinic, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - Evelina Simiene
- Eye Clinic, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | | | | | - Vytautas Petkus
- Health Telematics Science Institute, Kaunas University of Technology, Kaunas, Lithuania
| | - Arminas Ragauskas
- Health Telematics Science Institute, Kaunas University of Technology, Kaunas, Lithuania
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Arslan GD, Olgun A, Ozcan D, Gökcal E, Guven D, Asil T. Assessment of Cerebral Vasomotor Reactivity in Patients With Primary Open-angle Glaucoma and Ocular Hypertension Using the Breath-Holding Index. J Glaucoma 2021; 30:157-163. [PMID: 33074963 DOI: 10.1097/ijg.0000000000001711] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 10/03/2020] [Indexed: 11/26/2022]
Abstract
PRCIS Patients with ocular hypertension (OHT) do not show impaired cerebral vasodilation responses to hypercapnia but patients with primary open-angle glaucoma (POAG) do. Impaired vasoreactivity in patients with POAG may have neuronal or vascular origins and increase stroke risk. PURPOSE To investigate changes in cerebral blood flow and cerebral vasomotor reactivity using the breath-holding index in patients with POAG and OHT, to examine whether these parameters contribute to the risk of ischemic stroke. METHODS Thirty patients with POAG, 30 patients with OHT, and 30 age- and sex-matched healthy control subjects were included in this university hospital-based, cross-sectional, and observational study. Eyes with a greater degree of visual field loss and/or more severe optic disc damage were selected for the study in patients with POAG, whereas in patients with OHT and controls, the study eye was chosen randomly. The mean blood flow velocity and breath-holding index were measured in the middle cerebral artery ipsilaterally in patient and control groups, by using transcranial Doppler ultrasonography. RESULTS The mean blood flow velocity and breath-holding indexes were significantly lower in patients with POAG than in the control group (all P<0.05). In the OHT group, the mean blood flow velocity and breath-holding indexes were not different from those in the control group. CONCLUSIONS Patients with POAG have impaired vasodilation response to hypercapnia. Presumably, the neuronal changes and deterioration of the endothelium-mediated vasodilatation in patients with glaucoma may disrupt the regulation of arteries and potentially present functional insufficiency on vasoreactivity. Moreover, impaired cerebral vascular regulation may contribute to the increased risk of stroke in patients with POAG.
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Affiliation(s)
| | | | - Delil Ozcan
- Department of Ophthalmology, University of Health Sciences Şişli Hamidiye Etfal Training and Research Hospital
| | - Elif Gökcal
- Department of Neurology, Bezmialem Vakif University School of Medicine, Istanbul, Turkey
| | - Dilek Guven
- Department of Ophthalmology, University of Health Sciences Şişli Hamidiye Etfal Training and Research Hospital
| | - Talip Asil
- Department of Neurology, Bezmialem Vakif University School of Medicine, Istanbul, Turkey
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Reduced Cerebral Blood Flow in the Visual Cortex and Its Correlation With Glaucomatous Structural Damage to the Retina in Patients With Mild to Moderate Primary Open-angle Glaucoma. J Glaucoma 2019; 27:816-822. [PMID: 29952821 DOI: 10.1097/ijg.0000000000001017] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE Altered ocular and cerebral vascular autoregulation and vasoreactivity have been demonstrated in patients with primary open-angle glaucoma (POAG). In the present study, we investigated the correlations between reduced cerebral blood flow (CBF) in early and higher-tier visual cortical areas and glaucomatous changes in the retinas of patients with mild to moderate POAG. PATIENTS AND METHODS 3-dimensional pseudocontinuous arterial spin labelling magnetic resonance imaging at 3 T was performed in 20 normal controls and 15 mild to moderate POAG patients. Regions of interest were selected based on the Population-Average, Landmark- and Surface-based (PALS) atlas of the human cerebral cortex. Arterial spin labelling-measured CBF values were extracted in the early and higher-tier visual cortical areas and were compared between patients and controls using a 2-sample t test. Pearson correlation analyses were used to assess the correlations between reduced CBF and cup-to-disc ratio, retinal nerve fiber layer thickness, and ganglion cell complex thickness. RESULTS Reduced CBF in early visual cortical areas (V1, V2, and ventral posterior area) and in the higher-tier visual left lateral occipital cortex was presented in mild to moderate POAG patients compared with controls. Furthermore, reduced CBF of the right areas V2 and ventral posterior area was correlated with cup-to-disc ratio, total ganglion cell complex thickness, and average retinal nerve fiber layer thickness. CONCLUSIONS In conclusion, the complex pathologic progress of POAG includes abnormal cerebral perfusion within the visual cortex since the mild to moderate disease stages. The association of cerebral perfusion changes with alterations of the optic disc and the retina may contribute to the early diagnosis of POAG.
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Kurysheva NI. [Selective α2 agonists in the treatment of glaucoma: neuroprotective properties and impact on ocular blood flow]. Vestn Oftalmol 2019; 135:113-120. [PMID: 31393455 DOI: 10.17116/oftalma2019135031113] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Glaucoma is the main cause of irreversible blindness in the world. The selective α2 adrenergic receptor agonist brimonidine holds an important place among the hypotensive eye drops. The second part of this review focuses on some important effects of brimonidine that characterizes it as a medication with direct neuroprotective multifactorial action, discusses its influence on ocular blood flow and highlights its capability to maintain normal autoregulation of ocular blood flow.
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Affiliation(s)
- N I Kurysheva
- Ophthalmological Center of the Federal Medical-Biological Agency of the Russian Federation, State Research Center Burnasyan Federal Medical Biophysical Center of the Federal Medical-Biological Agency, Academy of postgraduate education under FSBU FSCC of FMBA of Russia, Department of Ophthalmology, 15 Gamalei St., Moscow, Russian Federation, 123098
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Engelhorn T, A Schmidt M, Dörfler A, Michelson G. [Diffusion tensor imaging of the visual pathway in glaucomatous optic nerve atrophy]. Ophthalmologe 2017; 114:906-921. [PMID: 28251307 DOI: 10.1007/s00347-017-0467-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
In Germany more than one million inhabitants suffer from glaucoma, more than 100,000 are threatened with blindness because glaucoma is often diagnosed too late or not at all. Diagnosis and monitoring is usually carried out "only" by examination of the retina and not the whole visual pathway. However, the eye is just "the tip of the iceberg" of the actual visual pathway, which extends through the brain to the visual cortex. The interdisciplinary holistic assessment of the whole visual pathway in glaucoma is of crucial importance because glaucoma is a complex neurodegenerative disease. Subtypes, such as normal tension glaucoma (NTG), seem to originate from primary damage to the intracranial visual pathway with secondary retrograde retinal degeneration. Recent studies including glaucoma patients and healthy controls could show that diffusion tensor imaging with calculation of diffusion coefficients, i.e. fractional anisotropy (FA), mean and radial diffusivity (MD and RD) as markers of axonal integrity, provide the potential to assess the intracranial visual pathway with a high correlation to established ophthalmological examinations. In particular, calculation of FA maps of the visual pathway and accompanying voxel-based approaches, can be integrated into clinical routine. Thus, detection of glaucoma-related intracranial alterations, even in early stages of the disease, as well as differentiation of different glaucoma subtypes, is made possible. Furthermore, the diagnosis of normal tension glaucoma seems to be possible much earlier with these new imaging techniques compared to established ophthalmological work-up. Moreover, holistic imaging provides new insights into the pathophysiology of this form of glaucoma. This review article gives an overview of these novel magnetic resonance imaging techniques for assessment of the visual pathway in glaucomatous optic nerve atrophy and reveals the potential of an interdisciplinary approach.
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Affiliation(s)
- T Engelhorn
- Neuroradiologische Abteilung, Schwabachanlage 6 (Kopfklinik), Friedrich-Alexander Universität Erlangen-Nürnberg, 91054, Erlangen, Deutschland.
| | - M A Schmidt
- Neuroradiologische Abteilung, Schwabachanlage 6 (Kopfklinik), Friedrich-Alexander Universität Erlangen-Nürnberg, 91054, Erlangen, Deutschland
| | - A Dörfler
- Neuroradiologische Abteilung, Schwabachanlage 6 (Kopfklinik), Friedrich-Alexander Universität Erlangen-Nürnberg, 91054, Erlangen, Deutschland
| | - G Michelson
- Klinik für Augenheilkunde, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, Deutschland
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Pasquale LR, Hanyuda A, Ren A, Giovingo M, Greenstein SH, Cousins C, Patrianakos T, Tanna AP, Wanderling C, Norkett W, Wiggs JL, Green K, Kang JH, Knepper PA. Nailfold Capillary Abnormalities in Primary Open-Angle Glaucoma: A Multisite Study. Invest Ophthalmol Vis Sci 2016; 56:7021-8. [PMID: 26523386 DOI: 10.1167/iovs.15-17860] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE There is considerable evidence for systemic vascular dysfunction in primary open-angle glaucoma (POAG). We performed nailfold capillary video microscopy to observe directly the nature of nonocular microvasculature abnormalities in POAG. METHODS We enrolled 199 POAG patients and 124 control subjects from four sites. We used JH-1004 capillaroscopes to perform nailfold capillary video microscopy on the fourth and fifth digits of each subject's nondominant hand. Videos were evaluated for hemorrhages, dilated capillary loops > 50 μm, and avascular zones > 100 μm by graders masked to case status. Multivariable odds ratios (ORs) and 95% confidence intervals (CIs) for POAG were obtained by means of logistic regression analyses that were applied to data from all cases and controls. Corresponding estimates of moderate or severe POAG versus mild POAG (based on the Hodapp-Anderson-Parrish scale) were obtained among cases only. RESULTS After controlling for demographic factors, family history of glaucoma, systemic diseases, and use of anticoagulation and antiplatelet therapy, for each 100 nailfold capillaries assessed, all types of microvascular abnormalities were significantly associated with POAG. Specifically, the presence of any dilated capillaries (OR = 2.9; 95% CI, 1.6-5.6), avascular zones (OR = 4.4; 95% CI, 1.7-11.3) and hemorrhages (OR = 12.2; 95% CI, 5.9-25.1) were associated with POAG. Among cases, the frequency of microvascular abnormalities was not associated with glaucoma severity (P ≥ 0.43). CONCLUSIONS These data provided support for nonocular capillary bed abnormalities in POAG. Comparable vascular abnormalities in the optic nerve may render it susceptible to glaucomatous damage.
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Affiliation(s)
- Louis R Pasquale
- Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts, United States 2Channing Division of Network Medicine, Department of Medicine, Brigham & Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Akiko Hanyuda
- Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, United States
| | - Ai Ren
- Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts, United States
| | - Michael Giovingo
- Department of Ophthalmology, John H. Stroger Jr Hospital of Cook County, Chicago, Illinois, United States
| | - Scott H Greenstein
- Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts, United States
| | - Clara Cousins
- Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts, United States
| | - Thomas Patrianakos
- Department of Ophthalmology, John H. Stroger Jr Hospital of Cook County, Chicago, Illinois, United States
| | - Angelo P Tanna
- Department of Ophthalmology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States
| | - Christopher Wanderling
- Department of Ophthalmology and Visual Sciences, University of Illinois College of Medicine at Chicago, Chicago, Illinois, United States
| | - William Norkett
- Department of Ophthalmology and Visual Sciences, University of Illinois College of Medicine at Chicago, Chicago, Illinois, United States
| | - Janey L Wiggs
- Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts, United States
| | - Kelsey Green
- Department of Ophthalmology and Visual Sciences, University of Illinois College of Medicine at Chicago, Chicago, Illinois, United States
| | - Jae H Kang
- Channing Division of Network Medicine, Department of Medicine, Brigham & Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States
| | - Paul A Knepper
- Department of Ophthalmology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States 6Department of Ophthalmology and Visual Sciences, University of Illinois College of Medicine at Chicago, Chicago, Illinois, United States
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Abstract
PURPOSE OF REVIEW The purpose of this review is to discuss whether vascular dysfunction and autonomic dysfunction are related to primary open-angle glaucoma stratified by the intraocular pressure (IOP) level. RECENT FINDINGS Patients with primary open angle glaucoma (POAG) across the spectrum of IOP exhibit a variety of ocular and nonocular vascular abnormalities. Interestingly, common genetic variation in nitric oxide synthase 3 (NOS3) and the caveolin 1/caveolin 2 (CAV1/CAV2) genomic regions, which code for proteins involved in setting vascular tone, are associated with POAG. These markers seem to stratify with POAG subtypes stratified by sex or pattern of initial visual field loss and not by IOP level. Overall, it is clear that there is also cardiovascular autonomic dysfunction in high-tension glaucoma and normal-tension glaucoma but it is unclear if this dysfunction is more common in normal-tension glaucoma compared with high-tension glaucoma. SUMMARY Overall, POAG is likely a heterogeneous disease but stratifying cases by IOP level associated with initial optic nerve damage may be less useful than using other endophenotype approaches. Embracing the evidence suggesting systemic endothelial and autonomic dysfunction are operative in POAG will help us move beyond an IOP-centric view of the disease and facilitate 'tearing down the wall' that divides treating physicians and a better understanding of POAG pathogenesis.
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Affiliation(s)
- Louis R. Pasquale
- Mass Eye and Ear Infirmary, 243 Charles Street, Boston, MA 02114
- Division of Network Medicine, Brigham and Women’s Hospital, 221 Longwood Avenue, Boston, MA 02115, Phone: 617-573-3674
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12
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Quill B, Henry E, Simon E, O'Brien CJ. Evaluation of the Effect of Hypercapnia on Vascular Function in Normal Tension Glaucoma. BIOMED RESEARCH INTERNATIONAL 2015; 2015:418159. [PMID: 26557667 PMCID: PMC4628756 DOI: 10.1155/2015/418159] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Accepted: 07/26/2015] [Indexed: 11/30/2022]
Abstract
INTRODUCTION Altered ocular perfusion and vascular dysregulation have been reported in glaucoma. The aim of this paper was to evaluate the vascular response to a hypercapnic stimulus. METHODS Twenty normal tension glaucoma (NTG) patients and eighteen age- and gender-matched controls had pulsatile ocular blood flow (POBF) measurements, systemic cardiovascular assessment, and laser Doppler digital blood flow (DBF) assessed. Measurements were taken at baseline, after 10-minutes rest, in the stable sitting and supine positions and following induction and stabilization of hypercapnia, which induced a 15% increase in end-tidal pCO2. The POBF response to hypercapnia was divided into high (>20%) and low responders (<20%). RESULTS 65% of NTG patients had a greater than 41% increase in POBF following CO2 rebreathing (high responders). These high responders had a lower baseline POBF, lower baseline DBF, and a greater DBF response to thermal stimulus. CONCLUSION NTG patients that have a greater than 20% increase in POBF after a hypercapnic stimulus have lower baseline POBF and DBF values. This suggests that there is impaired regulation of blood flow in a significant subgroup of NTG patients. This observation may reflect a generalised dysfunction of the vascular endothelium.
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Affiliation(s)
- B. Quill
- UCD School of Medicine and Medical Science, University College Dublin, Belfield, Dublin, Ireland
| | - E. Henry
- Princess Alexandra Eye Pavilion, Edinburgh, UK
| | - E. Simon
- Princess Alexandra Eye Pavilion, Edinburgh, UK
| | - C. J. O'Brien
- UCD School of Medicine and Medical Science, University College Dublin, Belfield, Dublin, Ireland
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Su CC, Chen JYC, Wang TH, Huang JY, Yang CM, Wang IJ. Risk factors for depressive symptoms in glaucoma patients: a nationwide case-control study. Graefes Arch Clin Exp Ophthalmol 2015; 253:1319-25. [PMID: 26047532 DOI: 10.1007/s00417-015-3032-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2015] [Revised: 04/15/2015] [Accepted: 04/20/2015] [Indexed: 11/25/2022] Open
Abstract
PURPOSE The purpose was to investigate the risk factors for depressive symptoms in glaucoma patients. METHODS From the Longitudinal Health Insurance Database in Taiwan, we included 1190 glaucoma patients with subsequent depression diagnoses in the case group and randomly selected 4673 glaucoma patients without depression diagnoses as the control group, matched by age, sex, and time of glaucoma diagnosis. The age-adjusted Charlson comorbidity index (ACCI) score was used to compute the burden of comorbidity for each patient. Current use (past 6 months) of topical antiglaucoma medications and systemic medications was identified. Multivariate regression was used to analyze the risk factors for depression. RESULTS The mean age for glaucoma patients was 61.88 years. Patients with depressive symptoms had significantly higher ACCI scores (P < .0001). The current use of any topical antiglaucoma medications was not associated with an increased risk for depression. However, higher ACCI scores (P < .0001), cerebrovascular diseases (odds ratio [OR] = 1.324, 95 % confidence interval [CI] = 1.118--1.568), dementia (OR = 2.647, 95 % CI = 2.142-3.270), thyroid diseases (OR = 1.720, 95 % CI = 1.366-2.165), headaches (OR = 1.299, 95 % CI = 1.112-1.518), and current use of systemic β-blockers (OR = 1.782, 95 % CI = 1.538-2.065) and calcium channel blockers (OR = 1.396, 95 % CI, 1.197-1.629) were found to increase the risk of depression in glaucoma patients. CONCLUSIONS In this study, a comorbidity burden was a significant risk factor for depression in glaucoma patients, particularly for those currently using systemic β-blockers and calcium channel blockers.
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Affiliation(s)
- Chien-Chia Su
- Department of Ophthalmology, National Taiwan University Hospital, Hsin-Chu Branch, Hsin-Chu, Taiwan
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14
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Sugiyama T. Glaucoma and Alzheimer's disease: Their clinical similarity and future therapeutic strategies for glaucoma. World J Ophthalmol 2014; 4:47-51. [DOI: 10.5318/wjo.v4.i3.47] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2014] [Revised: 04/30/2014] [Accepted: 07/14/2014] [Indexed: 02/06/2023] Open
Abstract
Glaucoma refers to a group of diseases characterized by optic neuropathies that are commonly associated with degeneration of the retinal ganglion cells. Although intraocular pressure (IOP) is the only proven treatable factor, several studies indicate that other factors are involved in the pathogenesis of glaucoma. Since normal tension glaucoma (NTG) is the most common glaucoma at least in Japan and South Korea, development of new therapeutic strategies for glaucoma, besides reduction of IOP, is crucial. The clinical characteristics and mechanisms underlying neuronal degeneration in Alzheimer’s disease, a progressive neurodegenerative disease, are similar to those of glaucoma. Impaired cerebral blood flow (CBF) is common to both these diseases; therefore, improving CBF may be considered a new treatment for glaucoma, especially for NTG. In addition, targeting the formation and aggravation pathway for amyloid-β and administration of apolipoprotein E-containing lipoproteins may be potential strategies for glaucoma treatment.
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15
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Nonstationarity of dynamic cerebral autoregulation. Med Eng Phys 2014; 36:576-84. [DOI: 10.1016/j.medengphy.2013.09.004] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Revised: 08/23/2013] [Accepted: 09/04/2013] [Indexed: 11/18/2022]
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16
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Dynamic cerebral autoregulation is compromised in ischaemic stroke of undetermined aetiology only in the non-affected hemisphere. Neurol Neurochir Pol 2014; 48:91-7. [DOI: 10.1016/j.pjnns.2013.12.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Accepted: 12/06/2013] [Indexed: 11/30/2022]
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17
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Higher optic nerve sheath diameters are associated with lower ocular blood flow velocities in glaucoma patients. Graefes Arch Clin Exp Ophthalmol 2013; 252:477-83. [PMID: 24281785 DOI: 10.1007/s00417-013-2533-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Revised: 11/03/2013] [Accepted: 11/13/2013] [Indexed: 12/25/2022] Open
Abstract
PURPOSE To investigate the relationship between optic nerve sheath diameter (ONSD) and retrobulbar blood flow velocities, as measured by color Doppler imaging (CDI) in glaucoma patients. METHODS We performed a prospective, randomized, observer-masked study involving a total of 197 subjects. Once enrolled, they were divided by three groups: healthy controls (n = 51), normal-tension glaucoma patients (NTG, n = 58), and primary, open-angle glaucoma patients (POAG, n = 88). All subjects underwent a general ophthalmological examination, an ultrasound-based assessment of the ONSD, and a hemodynamic study of the retrobulbar vascularization using CDI. Non-parametric tests, chi-square contingency tables, and the Deming correlations were used to explore differences and correlations between variables in the diagnostic groups. RESULTS ONSD was not different between experimental groups (p = 0.28). ONSD correlated positively with the pulsatility index of the ophthalmic artery in healthy individuals (p = 0.007), but not in glaucoma patients (NTG: p = 0.41; POAG: p = 0.22). In NTG patients, higher ONSD values were associated with lower end-diastolic and mean flow velocities in the short ciliary arteries (p = 0.005 in both correlations). No such correlation was found in healthy nor POAG groups (p range between 0.15 to 0.96). ONSD was not associated with any CDI-related variable of the central retinal artery in any cohort. Venous outflow velocities were not associated with ONSD in any of the three groups. CONCLUSIONS ONSD is negatively correlated with retrobulbar blood flow velocities in glaucoma patients, but not in healthy controls.
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Abstract
Glaucomatous damage has been described as a slowly progressive neuronal degenerative process along the visual pathway. Decreased cerebral and ocular blood flow as well as impaired vascular autoregulation has been identified in glaucoma and have been shown to correlate with visual field loss. In low-tension glaucoma patients, diffuse cerebral ischemic changes have been detected through magnetic resonance imaging. Given these findings, it seems that for some patients, glaucomatous damage may be the ocular manifestation of a more widespread vascular abnormality involving the brain rather than a separate process isolated only to the eye and its immediate vasculature.
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Affiliation(s)
- Alon Harris
- Department of Ophthalmology, Glick Eye Institute, Indiana University Medical Center, Indianapolis, IN, USA
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19
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Harazny JM, Schmieder RE, Welzenbach J, Michelson G. Local application of tropicamide 0.5% reduces retinal capillary blood flow. Blood Press 2013; 22:371-6. [PMID: 23597124 DOI: 10.3109/08037051.2013.782956] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
INTRODUCTION Scanning laser Doppler flowmetry (SLDF) plays an important role in the study of arterial hypertension, diabetes and stroke. The technology enables non-invasive measurement of the retinal capillary perfusion (RCF), retinal haemodynamics and arteriolar morphology in human. The values can be measured in mydriasis or in non-mydriatic eyes. It is not clear whether the using of vasoactive mydriatica for pupil dilation affects the measured parameters in retina. Acetylcholine, a vasoactive neurotransmitter in human retina, affects the contractility of pericytes using muscarinic receptors and stimulates endothelial synthesis of nitric oxide (NO). We examined whether blockade of the retinal cholinergic receptors by tropicamide affects the RCF. METHODS We measured RCF in both eyes of 13 healthy subjects before and 30 min after the local application of one drop of 0.5% tropicamide to the right eye. The mean age of the group was 44 ± 14 years. The left eye was used as control. RCF was measured by Heidelberg retina flowmetry. RESULTS Thirty minutes after local application of one drop of 0.5% tropicamide to the right eye RCF decreased significantly (p = 0.001) by 31.9 ± 13% but did not change in the control eye. The maximal decrease was observed 20 min after application of the tropicamide. CONCLUSION Locally administered tropicamide profoundly affects the RCF. Thus pupil dilatation impairs any assessment of retinal microcirculation.
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Affiliation(s)
- Joanna M Harazny
- Ophthalmology Department Friedrich-Alexander University , Erlangen , Germany
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20
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Mroczkowska S, Ekart A, Sung V, Negi A, Qin L, Patel SR, Jacob S, Atkins C, Benavente-Perez A, Gherghel D. Coexistence of macro- and micro-vascular abnormalities in newly diagnosed normal tension glaucoma patients. Acta Ophthalmol 2012; 90:e553-9. [PMID: 22998650 DOI: 10.1111/j.1755-3768.2012.02494.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
PURPOSE To investigate the coexistence of ocular microvascular and systemic macrovascular abnormalities in early stage, newly diagnosed and previously untreated normal tension glaucoma patients (NTG). METHODS Retinal vascular reactivity to flickering light was assessed in 19 NTG and 28 age-matched controls by means of dynamic retinal vessel analysis (IMEDOS GmbH, Jena, Germany). Using a newly developed computational model, the entire dynamic vascular response profile to flicker light was imaged and used for analysis. In addition, assessments of carotid intima-media thickness (IMT) and pulse wave analysis (PWA) were conducted on all participants, along with blood pressure (BP) measurements and blood analyses for lipid metabolism markers. RESULTS Patients with NTG demonstrated an increased right and left carotid IMT (p = 0.015, p = 0.045) and an elevated PWA augmentation index (p = 0.017) in comparison with healthy controls, along with an enhanced retinal arterial constriction response (p = 0.028), a steeper retinal arterial constriction slope (p = 0.031) and a reduced retinal venous dilation response (p = 0.026) following flicker light stimulation. CONCLUSIONS Early stage, newly diagnosed, NTG patients showed signs of subclinical vascular abnormalities at both macro- and micro-vascular levels, highlighting the need to consider multi-level circulation-related pathologies in the development and progression of this type of glaucoma.
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Affiliation(s)
- Stephanie Mroczkowska
- Vascular Research Laboratory, Ophthalmic Research Group, School of Life and Health Sciences, Aston University, Birmingham, UK
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Moore D, Harris A, Wudunn D, Kheradiya N, Siesky B. Dysfunctional regulation of ocular blood flow: A risk factor for glaucoma? Clin Ophthalmol 2011; 2:849-61. [PMID: 19668439 PMCID: PMC2699797 DOI: 10.2147/opth.s2774] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Primary open angle glaucoma (OAG) is a multifactorial optic neuropathy characterized by progressive retinal ganglion cell death and associated visual field loss. OAG is an emerging disease with increasing costs and negative outcomes, yet its fundamental pathophysiology remains largely undetermined. A major treatable risk factor for glaucoma is elevated intraocular pressure (IOP). Despite the medical lowering of IOP, however, some glaucoma patients continue to experience disease progression and subsequent irreversible vision loss. The scientific community continues to accrue evidence suggesting that alterations in ocular blood flow play a prominent role in OAG disease processes. This article develops the thesis that dysfunctional regulation of ocular blood flow may contribute to glaucomatous optic neuropathy. Evidence suggests that impaired vascular autoregulation renders the optic nerve head susceptible to decreases in ocular perfusion pressure, increases in IOP, and/or increased local metabolic demands. Ischemic damage, which likely contributes to further impairment in autoregulation, results in changes to the optic nerve head consistent with glaucoma. Included in this review are discussions of conditions thought to contribute to vascular regulatory dysfunction in OAG, including atherosclerosis, vasospasm, and endothelial dysfunction.
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Affiliation(s)
- Danny Moore
- Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, IN, USA
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22
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Feke GT, Hazin R, Grosskreutz CL, Pasquale LR. Effect of brimonidine on retinal blood flow autoregulation in primary open-angle glaucoma. J Ocul Pharmacol Ther 2011; 27:347-52. [PMID: 21631365 DOI: 10.1089/jop.2011.0014] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
PURPOSE To determine whether topically applied brimonidine affects the retinal hemodynamic autoregulatory response to posture change in patients with normal tension glaucoma. METHODS Six patients with normal tension glaucoma (primary open-angle glaucoma and maximum untreated intraocular pressure <22 mmHg) in each eye were studied. We retrospectively reviewed retinal hemodynamic data acquired when the patients were off and on treatment with brimonidine 0.15% (twice a day, both eyes) during the course of their care. At each testing session, vessel diameter and blood speed at the same site along the inferior temporal retinal artery of 1 eye were measured while sitting, while reclining for 30 min, and again while sitting using a retinal laser Doppler instrument. Blood flow was computed automatically. Brachial artery blood pressure and heart rate were also measured. The Wilcoxon signed rank test was used to assess the statistical significance of the differences in each measured parameter while subjects were on and off brimonidine. RESULTS Off brimonidine, the mean blood flow rate increased by 68.0%±34.3% (range: +17% to +108%) after 30 min in reclined posture compared to baseline-seated measures. On brimonidine, the mean blood flow rate increased by 8.9%±16.8% (range: -9.7 to +28.0%) after 30 min in reclined posture compared to baseline-seated measures. The difference in the posture-induced changes for blood flow rate while on brimonidine compared to off brimonidine was statistically significant (P=0.027). CONCLUSIONS Off brimonidine, the patients exhibited marked increases in retinal blood flow while reclining. On brimonidine, the hemodynamic changes were consistent with normal autoregulatory control of retinal blood flow.
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Affiliation(s)
- Gilbert T Feke
- Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, MA 02114, USA
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23
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Mozaffarieh M, Osusky R, Schotzau A, Flammer J. Relationship between optic nerve head and finger blood flow. Eur J Ophthalmol 2010; 20:136-41. [PMID: 19882525 DOI: 10.1177/112067211002000119] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE To examine the relationship between optic nerve head (ONH) and finger blood flow in subjects with and without a primary vascular dysregulation (PVD). METHODS ONH blood flow and finger blood flow was measured in 15 subjects with PVD and in 24 subjects without PVD. PVD was defined as being present if it was detected in patient history as well as by nailfold capillaromicroscopy. PVD was defined as being absent if the patient history for PVD was negative and the results of nailfold capillaromicroscopy were negative. Scanning laser Doppler flowmetry (LDF) was used to measure ONH and finger blood flow. Finger temperature was measured in all subjects using a contact sensor. RESULTS ONH blood flow is significantly related to finger blood flow in subjects with PVD (p<0.01), but not in subjects without a PVD. Subjects with PVD had a significantly lower finger skin temperature in comparison to those without PVD (p<0.01) CONCLUSIONS The present study indicates a relationship between ONH and finger blood flow in subjects with PVD. This might be an indirect sign of a disturbed autoregulation of ocular blood flow in PVD subjects.
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Affiliation(s)
- Jau-Der Ho
- From the Department of Ophthalmology (J.-D.H.), Taipei Medical University Hospital, Taipei, Taiwan; the Department of Ophthalmology (J.-D.H.), Taipei Medical University, Taipei, Taiwan; the Department of Ophthalmology (C.-C.H.), Shin Kong Wu-Ho Su Memorial Hospital, Taipei, Taiwan; and the School of Health Care Administration (C.-C.H., H.-C.L.), Taipei Medical University, Taipei, Taiwan
| | - Chao-Chien Hu
- From the Department of Ophthalmology (J.-D.H.), Taipei Medical University Hospital, Taipei, Taiwan; the Department of Ophthalmology (J.-D.H.), Taipei Medical University, Taipei, Taiwan; the Department of Ophthalmology (C.-C.H.), Shin Kong Wu-Ho Su Memorial Hospital, Taipei, Taiwan; and the School of Health Care Administration (C.-C.H., H.-C.L.), Taipei Medical University, Taipei, Taiwan
| | - Herng-Ching Lin
- From the Department of Ophthalmology (J.-D.H.), Taipei Medical University Hospital, Taipei, Taiwan; the Department of Ophthalmology (J.-D.H.), Taipei Medical University, Taipei, Taiwan; the Department of Ophthalmology (C.-C.H.), Shin Kong Wu-Ho Su Memorial Hospital, Taipei, Taiwan; and the School of Health Care Administration (C.-C.H., H.-C.L.), Taipei Medical University, Taipei, Taiwan
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Abstract
Short-term regulation of cerebral blood flow (CBF) is controlled by myogenic, metabolic and neurogenic mechanisms, which maintain flow within narrow limits, despite large changes in arterial blood pressure (ABP). Static cerebral autoregulation (CA) represents the steady-state relationship between CBF and ABP, characterized by a plateau of nearly constant CBF for ABP changes in the interval 60-150 mmHg. The transient response of the CBF-ABP relationship is usually referred to as dynamic CA and can be observed during spontaneous fluctuations in ABP or from sudden changes in ABP induced by thigh cuff deflation, changes in posture and other manoeuvres. Modelling the dynamic ABP-CBFV relationship is an essential step to gain better insight into the physiology of CA and to obtain clinically relevant information from model parameters. This paper reviews the literature on the application of CA models to different clinical conditions. Although mathematical models have been proposed and should be pursued, most studies have adopted linear input-output ('black-box') models, despite the inherently non-linear nature of CA. The most common of these have been transfer function analysis (TFA) and a second-order differential equation model, which have been the main focus of the review. An index of CA (ARI), and frequency-domain parameters derived from TFA, have been shown to be sensitive to pathophysiological changes in patients with carotid artery disease, stroke, severe head injury, subarachnoid haemorrhage and other conditions. Non-linear dynamic models have also been proposed, but more work is required to establish their superiority and applicability in the clinical environment. Of particular importance is the development of multivariate models that can cope with time-varying parameters, and protocols to validate the reproducibility and ranges of normality of dynamic CA parameters extracted from these models.
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Feke GT, Pasquale LR. Retinal blood flow response to posture change in glaucoma patients compared with healthy subjects. Ophthalmology 2007; 115:246-52. [PMID: 17689612 DOI: 10.1016/j.ophtha.2007.04.055] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2006] [Revised: 04/12/2007] [Accepted: 04/13/2007] [Indexed: 11/16/2022] Open
Abstract
PURPOSE To characterize the retinal vascular autoregulatory response to ocular perfusion pressure (OPP) changes in patients with glaucoma and in healthy control subjects. DESIGN Observational cohort study. PARTICIPANTS Eighteen patients with open-angle glaucoma (OAG) and 8 control subjects, all females ages 40 to 60 years, were studied. Only subjects with known maximum intraocular pressure less than 22 mmHg in both eyes were included. METHODS Arterial diameter and blood speed in the inferior temporal retinal artery of the left eye were measured simultaneously at baseline while sitting, while reclining for approximately 30 minutes, and once again sitting using a retinal laser Doppler instrument. Blood flow rate was computed automatically. Brachial artery blood pressure and heart rate also were measured. MAIN OUTCOME MEASURE Change in blood flow rate while reclining for approximately 30 minutes compared with baseline blood flow rate measured while seated. RESULTS In control subjects, arterial diameter decreased by 7.5+/-3.4% (P = 0.0003) and blood speed increased by 24.6+/-10.8% (P = 0.004) while reclining compared with baseline. The concomitant change in the blood flow rate (6.5+/-12.0%; P = 0.15) compared with baseline was not statistically significant. In contrast, OAG patients showed a much broader range of blood flow changes in response to posture change (14.9+/-37.7%; P = 0.086) compared with baseline. Although there were no significant differences in the flow changes compared with baseline in either group, there was a significant difference in the variance of the blood flow changes in the OAG patients compared with the controls (P = 0.0025). Division of the OAG patients into subgroups revealed a significant (P = 0.031) association between baseline OPP and the retinal blood flow response to posture change. CONCLUSIONS The authors describe the hemodynamic details of retinal vascular autoregulation in response to posture-induced changes in OPP in healthy subjects and document the lack of such autoregulation in a selected group of patients with OAG.
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Affiliation(s)
- Gilbert T Feke
- Schepens Retina Associates Foundation, Boston, Massachusetts 02215, USA.
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27
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Zeitz O, Wagenfeld L, Wirtz N, Galambos P, Matthiesen N, Wiermann A, Richard G, Klemm M. Influence of oxygen free radicals on the tone of ciliary arteries: a model of vasospasms of ocular vasculature. Graefes Arch Clin Exp Ophthalmol 2007; 245:1327-33. [PMID: 17252259 DOI: 10.1007/s00417-006-0526-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2006] [Revised: 12/11/2006] [Accepted: 12/12/2006] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Altered regulation of vascular tone and particularly vasospasms are thought to be a risk factor for the progression of primary open angle glaucoma (POAG). Apoptosis of retinal ganglion cells and possibly vascular tone regulation in glaucoma might be caused by oxidative stress. The aim of the present study was to investigate the influence of oxygen free radicals on the tone of ciliary arteries. METHODS The experiments were carried out with fresh ring preparations from porcine ciliary arteries obtained from a slaughterhouse. The preparations were placed in a self-designed myograph system and were kept under physiologic conditions (pH 7.4, 37 degrees C, Krebs-Henseleit-Buffer, 1.75 mM Ca(2+)). The muscles were sub-maximally activated by depolarization to -41 mV Nernst potential for K(+). The pre-activated preparations were exposed to hydroxyl radicals generated by the Fenton reaction (4 mM H(2)O(2); 30 microM Fe(3+)). Exposure time varied between 10 s and 60 s in order to obtain different radical-time-doses. The developed force was evaluated relatively to the developed force at maximal depolarization to -4 mV. RESULTS Ten seconds of radical exposure result in an additional increase of the relative developed force from 0.35 +/- .08 to 0.62 +/- 0.12 (P = 0.003; n = 8). Comparable results were obtained for 20 s and 60 s radical exposures. The developed force of a maximal activation to -4 mV was not reduced after a 10 s radical exposure (0.84 +/- 0.13; P = 0.25; n = 5), but was significantly reduced after 20 s exposure (0.25 +/- 0.21; P = 0.005; n = 6) and was virtually 0 after 60 s exposure. DISCUSSION The data shows that oxygen free radicals induce transient contractions of isolated ciliary artery rings. The shape of these contractions shows parallels to vasospasms. Thus the established system may serve as an in vitro model of vasospasms.
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Affiliation(s)
- Oliver Zeitz
- Klinik und Poliklinik für Augenheilkunde, Universitätsklinikum Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany.
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Galambos P, Vafiadis J, Vilchez SE, Wagenfeld L, Matthiessen ET, Richard G, Klemm M, Zeitz O. Compromised Autoregulatory Control of Ocular Hemodynamics in Glaucoma Patients after Postural Change. Ophthalmology 2006; 113:1832-6. [PMID: 16920194 DOI: 10.1016/j.ophtha.2006.05.030] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2005] [Revised: 05/23/2006] [Accepted: 05/26/2006] [Indexed: 11/17/2022] Open
Abstract
PURPOSE The autoregulatory control of retrobulbar blood flow in response to postural challenge was investigated in normal-tension glaucoma (NTG) patients in comparison with primary open-angle glaucoma (POAG) patients and healthy volunteers. DESIGN Prospective cohort study. PARTICIPANTS AND CONTROLS Twenty POAG patients, 20 NTG patients, and 20 control subjects. METHODS Peak systolic velocity (PSV), end diastolic velocity (EDV), and resistivity index (RI) in the short posterior ciliary artery (SPCA), central retinal artery (CRA) and ophthalmic artery (OA) were recorded after a change from sitting upright to a supine body position using color Doppler imaging. MAIN OUTCOME MEASURES Peak systolic velocity, EDV, and RI. RESULTS Ten minutes after postural change to a supine position, blood flow velocities in the SPCA remained unchanged in controls, whereas a significant increase of PSV and EDV was found in both glaucoma groups. The RI in the SPCA was significantly lowered in the NTG group. Recordings for the OA and CRA showed a significant increase in EDV and significant decrease in RI in all 3 groups; a significant increase in PSV in the CRA was detected only in the NTG group. CONCLUSIONS The unaltered flow velocities in the SPCA of healthy controls may indicate tight autoregulatory control, whereas the flow velocities in the CRA and OA appeared to follow alterations in hydrostatic pressure. In contrast, NTG and POAG patients demonstrated an insufficient compensatory response to postural change, leading to accelerated flow in the SPCA. This compromised autoregulatory control could represent another contributing factor in the pathogenesis of glaucoma.
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Affiliation(s)
- Peter Galambos
- Glaukomlabor, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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Horn FK, Michelson G, Schnitzler E, Mardin CY, Korth M, Jünemann AG. Visual evoked potentials of the blue-sensitive pathway under cold provocation in normals and glaucomas. J Glaucoma 2006; 15:17-22. [PMID: 16378012 DOI: 10.1097/01.ijg.0000196656.23578.1b] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Vascular dysregulation in open-angle glaucomas can be identified by measuring the blood circulation during exposure to cold water. Aim of this study was to find out whether the same cold stimulus would lead to functional changes in the visual evoked potentials (VEP) of the short-sensitive pathway in normals and glaucoma patients. PATIENTS AND METHODS Blue-on-yellow pattern-visual evoked potentials were studied in 22 healthy control persons and 47 patients with primary open-angle glaucoma (25 high-pressure glaucomas, 22 normal pressure glaucomas with clinical signs of vasospastic hyperreactivity). A blue stripe pattern, presented in onset-offset mode on a yellow adaptation light served as the stimulus. Cold provocation was initiated by dipping one hand of the patient into cold water of 3 degrees C to 5 degrees C. The onset amplitudes and peak times were measured without cold exposition as well as two and four minutes after the cold exposition began. RESULTS In the group of vasospastic glaucoma patients a significant reduction of visual evoked potential-amplitudes was observed during cold provocation (amplitude before ice exposition: 4.17 microV, amplitude following two minutes of ice exposition: 3.52 microV; paired test: P < 0.01). Other subject groups showed no significant amplitude reductions after cold provocation. Peak times of both open-angle glaucoma groups (132.3 +/- 18.7 milliseconds in high pressure, 132.7 +/- 14.5 milliseconds in normal pressure) were significantly increased in comparison to normals (117.4 +/- 8.0 milliseconds). However, no significant influence of the cold provocation on peak times could be found in all groups. CONCLUSION Peak times of the blue-on-yellow visual evoked potentials are significantly prolonged in patients with primary open-angle glaucomas. Cold provocation causes a significant amplitude reduction of the blue-on-yellow visual evoked potential in the present normal-pressure glaucoma patients and reflects vascular dysregulation in patients with vasospastic hyperreactivity.
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Affiliation(s)
- Folkert K Horn
- Department of Ophthalmology and University Eye Hospital, Friedrich-Alexander University Erlangen-Nürnberg at Erlangen, Germany.
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