1
|
Konieczka K, Flammer J. Treatment of Glaucoma Patients with Flammer Syndrome. J Clin Med 2021; 10:4227. [PMID: 34575340 PMCID: PMC8467118 DOI: 10.3390/jcm10184227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 09/06/2021] [Accepted: 09/13/2021] [Indexed: 11/16/2022] Open
Abstract
Flammer syndrome (FS) describes a phenotype characterized by the presence of primary vascular dysregulation along with a number of symptoms and signs. Although most people with FS are healthy, FS favors the occurrence of certain diseases, such as normal tension glaucoma. This is because disturbed autoregulation makes the eye more sensitive to intraocular pressure (IOP) spikes or blood pressure drops. Treatment of FS is generally appropriate when patients either suffer greatly from their symptoms or if we can assume that it has contributed to a disease. In glaucoma, this may be the case if the glaucoma damage progresses despite well-controlled IOP. Both the still sparse scientific studies and our long clinical experience suggest that FS-targeted therapy not only relieves the symptoms of FS but also slows the progression of glaucoma damage in selected cases. This description is intended not only to help affected patients but to also motivate clinicians and researchers to conduct therapy studies to confirm or refute our observations.
Collapse
|
2
|
Salari N, Bokaee S, Farshchian N, Mohammadi M, Kazeminia M. The role of polymorphisms rs2070744 and rs1799983 eNOS gene in patients with POAG: a systematic review and meta-analysis. Int Ophthalmol 2021; 41:2747-2763. [PMID: 33837898 DOI: 10.1007/s10792-021-01832-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Accepted: 03/29/2021] [Indexed: 10/21/2022]
Abstract
BACKGROUND Glaucoma is a progressive disease of the optic nerve that has several underlying causes, but in most cases, the cause is unknown. Given the importance of the role of nitric oxide in the occurrence of ocular nerve damage and the effect of eNOS gene polymorphic sites on protein function, to better understand the mechanism of formation of POAG, the relationship between polymorphisms rs2070744 and rs1799983 eNOS gene with POAG risk was investigated in this study using meta-analysis. METHODS In this study, systematic review and meta-analysis of study data related to the study of polymorphisms rs2070744 and rs1799983 eNOS gene in patients with POAG using the keywords eNOS, NOS3, Gluuc8898, POAG, primary open-angle glaucoma. It was extracted from SID, MagIran, IranMedex, IranDoc, ScienceDirect, Embase, Scopus, PubMed, Web of Science, and Google Scholar search engines without a time limit until May 2020. To perform the analysis of qualified studies, the model of random effects was used and the inconsistency of studies with the I2 index was investigated. Data analysis was performed with Comprehensive Meta-Analysis (Version 2). RESULTS In a review of 16 studies (9 studies on polymorphism rs2070744 and seven studies on polymorphism rs1799983) with a sample size of 1631 subjects and a control group of 2405 subjects related to polymorphism rs2070744 and a group of 1456 subjects and a control group of 2240 subjects related to polymorphism 9997 rs1, the odds ratio of TT, CT, and CC genotypes was reported to be 0.95, 1.01, and 1.14, respectively, and the odds ratio of GG, GT and TT genotypes to be 0.88, 0.97, and 1.31, respectively, was reported in patients with POAG. CONCLUSION The results of our systematic review and meta-analysis study show that the eNOS gene polymorphisms rs2070744 and rs1799983 may increase the risk of POAG among individuals. However, further studies are needed to confirm these findings.
Collapse
Affiliation(s)
- Nader Salari
- Department of Biostatistics, School of Health, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Shadi Bokaee
- Faculty of Health and Life Sciences, School of Life Sciences, Coventry University, Coventry, UK
| | - Nushin Farshchian
- Department of Ophthalmology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Masoud Mohammadi
- Department of Nursing, School of Nursing and Midwifery, Kermanshah University of Medical Sciences, Kermanshah, Iran.
| | - Mohsen Kazeminia
- Student Research Committee, Kermanshah University of Medical Sciences, Kermanshah, Iran
| |
Collapse
|
3
|
Terelak-Borys B, Grabska-Liberek I, Schoetzau A, Konieczka K. Transient visual field impairment after cold provocation in glaucoma patients with Flammer syndrome. Restor Neurol Neurosci 2019; 37:31-39. [PMID: 30741709 PMCID: PMC6484275 DOI: 10.3233/rnn-180866] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Background: It is still debatable whether visual field defects in glaucoma have a reversible component and to what extent a temporary loss can be provoked. Objective: To investigate the response of the visual function to a cold provocation in glaucoma patients, particularly to test whether subjects with Flammer syndrome (FS) behaved differently from subjects without FS. Methods: Ten (10) primary open-angle glaucoma (POAG) patients with FS, 7 POAG patients without FS, and 11 healthy controls were tested with program G2 on the Octopus 101 perimeter before and after putting one hand in cold water (4°C) for 2 min. The mean sensitivity (MS) of each visual field was included in the statistical analysis. Results: In glaucoma patients with FS, the mean MS significantly decreased after cold provocation (delta MS = –0.91 dB, CI = –1.43 to –0.39, p = 0.0014). In contrast, the mean MS in glaucoma patients without FS did not change significantly (delta MS = 0.17 dB, CI = –0.43 to 0.78, p = 0.56). Likewise, the mean MS did not change significantly in the healthy controls (delta MS = 0.23 dB, CI = –0.27 to 0.72, p = 0.36). Conclusions: Cold provocation induced a transient visual field deterioration in the glaucoma patients with FS but not in the glaucoma patients without FS or in the healthy controls. We assume this effect to be the result of a transient reduction of ocular blood flow.
Collapse
Affiliation(s)
- Barbara Terelak-Borys
- Department of Ophthalmology, Centre of Postgraduate Medical Education, Warsaw, Poland
| | - Iwona Grabska-Liberek
- Department of Ophthalmology, Centre of Postgraduate Medical Education, Warsaw, Poland
| | - Andreas Schoetzau
- Department of Ophthalmology, University of Basel, Basel, Switzerland
| | | |
Collapse
|
4
|
Konieczka K, Erb C. Diseases potentially related to Flammer syndrome. EPMA J 2017; 8:327-332. [PMID: 29209435 PMCID: PMC5700007 DOI: 10.1007/s13167-017-0116-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Accepted: 08/22/2017] [Indexed: 02/03/2023]
Abstract
Flammer syndrome (FS) is a prevalent and mostly benign condition. Subjects with FS seem to have a good life expectancy. Nevertheless, FS subjects are at increased risk for certain diseases, mainly when they are challenged by psychological stress or other stimuli such as coldness. FS is related to ocular diseases, such as normal-tension glaucoma, retinitis pigmentosa, central serous chorioretinopathy, optic nerve compartment syndrome, Leber’s hereditary optic neuropathy, arterial or venous occlusions in the retina, and choroid and optic nerve head, despite the absence of classical vascular risk factors. FS is also related to some non-ocular diseases, such as multiple sclerosis, breast cancer, and altitude sickness. The role of FS in other diseases such as tinnitus, sudden hearing loss, Ménière’s disease, anorexia nervosa, and thyroid dysfunction is currently under investigation. The exact relationship of FS to related diseases however still needs to be established. This may hopefully lead to more targeted diagnostics and personalized treatments.
Collapse
Affiliation(s)
- Katarzyna Konieczka
- Department of Ophthalmology, University of Basel, Mittlere Strasse 91, CH-4031 Basel, Switzerland
| | - Carl Erb
- Eye Clinic Wittenbergplatz, Berlin, Germany
| |
Collapse
|
5
|
Flammer J, Konieczka K. The discovery of the Flammer syndrome: a historical and personal perspective. EPMA J 2017; 8:75-97. [PMID: 28725290 PMCID: PMC5486542 DOI: 10.1007/s13167-017-0090-x] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Accepted: 03/27/2017] [Indexed: 12/21/2022]
Abstract
This review describes the clinical and basic research that led to the description of Flammer syndrome. It is narrated from a personal perspective. This research was initiated by the observation of an increased long-term fluctuation of visual fields in a subgroup of glaucoma patients. As these patients had strikingly cold hands, peripheral blood flow was tested with a capillary microscopy, and vasospastic syndrome (VS) was diagnosed. Further studies on these patients revealed frequently weakened autoregulation of ocular blood flow and increased flow resistivity in retroocular vessels. Their retinal vessels were more rigid and irregular and responded less to flickering light. Holistic investigation demonstrated low blood pressure, silent myocardial ischaemia, altered beat-to-beat variation, altered gene expression in the lymphocytes, slightly increased plasma endothelin level and increased systemic oxidative stress. This combination of signs and symptoms was better described by the term primary vascular dysregulation (PVD) than by VS. Subsequent studies showed additional symptoms frequently related to PVD, such as low body mass index, cold extremities combined with slightly increased core temperature, prolonged sleep onset time, reduced feelings of thirst, increased sensitivity to smell and also for certain drugs and increased retinal venous pressure. To better characterise this entire syndrome, the term Flammer syndrome (FS) was introduced. Most subjects with FS were healthy. Nevertheless, FS seemed to increase the risk for certain eye diseases, particularly in younger patients. This included normal-tension glaucoma, anterior ischaemic optic neuropathy, retinal vein occlusions, Susac syndrome and central serous chorioretinopathy. Hereditary diseases, such as Leber’s optic neuropathy or retinitis pigmentosa, were also associated with FS, and FS symptoms and sings occurred more frequent in patients with multiple sclerosis or with acute hearing loss. Further research should lead to a more concise definition of FS, a precise diagnosis and tools for recognizing people at risk for associated diseases. This may ultimately lead to more efficient and more personalised treatment.
Collapse
Affiliation(s)
- Josef Flammer
- Department of Ophthalmology, University of Basel, Mittlere Strasse 91, CH-4031 Basel, Switzerland
| | - Katarzyna Konieczka
- Department of Ophthalmology, University of Basel, Mittlere Strasse 91, CH-4031 Basel, Switzerland
| |
Collapse
|
6
|
Moschos MM, Moustafa GA, Papakonstantinou VD, Tsatsos M, Laios K, Antonopoulou S. Anti-platelet effects of anti-glaucomatous eye drops: an in vitro study on human platelets. DRUG DESIGN DEVELOPMENT AND THERAPY 2017; 11:1267-1272. [PMID: 28458520 PMCID: PMC5402915 DOI: 10.2147/dddt.s131582] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
PURPOSE Altered platelet aggregability has been implicated in the pathogenesis of glaucoma. This study aims to investigate the anti-platelet potential of intraocular pressure lowering drops, with the possibility of establishing it as an additional mechanism of anti-glaucomatous action. MATERIALS AND METHODS The anti-aggregating effects of a series of anti-glaucomatous eye drops were determined on human platelets in the platelet aggregation model, using four known aggregating factors (platelet activating factor [PAF], adenosine diphosphate [ADP], thrombin receptor-activating peptide [TRAP], and arachidonic acid [AA]). RESULTS Almost all of the tested samples inhibited platelet aggregation induced by PAF, ADP, TRAP, and AA, except for Alphagan, which did not demonstrate inhibition of ADP- and TRAP-induced aggregation at a wide range of concentrations. Trusopt, Betoptic, and Azarga eye drops were the most potent inhibitors of all four aggregating factors, while Alphagan was the least potent (P<0.05). CONCLUSION This study shows that anti-glaucomatous eye drops possess anti-platelet effects, and this was shown for the first time by experimenting on human platelets.
Collapse
Affiliation(s)
- Marilita M Moschos
- 1st Department of Ophthalmology, Medical School, University of Athens, Athens, Greece.,Biomedical Research Foundation, Academy of Athens, Athens, Greece
| | - Giannis A Moustafa
- 1st Department of Ophthalmology, Medical School, University of Athens, Athens, Greece
| | - Vasiliki D Papakonstantinou
- Laboratory of Biology, Biochemistry, Physiology and Microbiology, Department of Nutrition and Dietetics, School of Health Science and Education, Harokopio University, Athens, Greece
| | - Michael Tsatsos
- Royal Eye Infirmary, Dorset County Hospital NHS Foundation Trust, Dorchester, UK
| | - Konstantinos Laios
- 1st Department of Ophthalmology, Medical School, University of Athens, Athens, Greece
| | - Smaragdi Antonopoulou
- Laboratory of Biology, Biochemistry, Physiology and Microbiology, Department of Nutrition and Dietetics, School of Health Science and Education, Harokopio University, Athens, Greece
| |
Collapse
|
7
|
Lee NY, Park HYL, Park CK. Comparison of the Effects of Dorzolamide/Timolol Fixed Combination versus Latanoprost on Intraocular Pressure and Ocular Perfusion Pressure in Patients with Normal-Tension Glaucoma: A Randomized, Crossover Clinical Trial. PLoS One 2016; 11:e0146680. [PMID: 26756747 PMCID: PMC4710520 DOI: 10.1371/journal.pone.0146680] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Accepted: 12/14/2015] [Indexed: 01/11/2023] Open
Abstract
BACKGROUD To assess the noninferiority of a dorzolamide-timolol fixed combination (DTFC) versus latanoprost in terms of intraocular pressure (IOP) and to compare blood pressure (BP), ocular perfusion pressure (OPP) and diastolic ocular perfusion pressure (DOPP) between the latanoprost and DTFC groups in patients with normal-tension glaucoma (NTG). METHODS Prospective, interventional, randomized, single-blinded, crossover design study. Patients with newly diagnosed NTG that had not been treated with a glaucoma medication in the most recent 2 months were recruited. In total, 44 patients with NTG were randomly allocated to one of two groups. Patients in group A were treated with DTFC, lubricant, and latanoprost for 4 weeks each, whereas patients in group B were treated with latanoprost, lubricant, and DTFC for 4 weeks each. Patients were examined on day 1 (without medication), week 4 (under medication), week 8 (without medication), and week 12 (under medication). At weeks 4 and 12, diurnal IOP, systolic and diastolic BP, and OPP were measured at 8:00 AM, 10:00 AM, 12:00 PM, 4:00 PM, and 8:00 PM. RESULTS Baseline demographic characteristics showed no difference in terms of age, sex, central corneal thickness, spherical equivalent, or stage of glaucoma between the groups. The between-group difference was -0.19 ± 0.18 mmHg (mean ± SE, upper bound of one-sided 95% CI, 0.12). Diurnal IOP showed no difference between the groups with an average IOP reduction of 13.1% using latanoprost and 12.3% using DTFC. Diurnal systolic and diastolic BP were lower in the DTFC group than the latanoprost group; however, the difference between the groups was not statistically significant. Diurnal OPP and DOPP also showed no statistically significant difference between the groups. CONCLUSIONS IOP lowering efficacy of DTFC was noninferior to that of latanoprost in newly diagnosed NTG patients. There was no difference in BP, OPP, or DOPP between the latanoprost and DTFC groups. This prospective, randomized, single-blinded, crossover study demonstrated the noninferiority of DTFC versus latanoprost in terms of IOP in patients with NTG. TRIAL REGISTRATION ClinicalTrials.gov NCT01175902.
Collapse
Affiliation(s)
- Na Young Lee
- Department of Ophthalmology and Visual Science, College of Medicine, Incheon St. Mary's Hospital, The Catholic University of Korea, Incheon, Korea
| | - Hae-Young Lopilly Park
- Department of Ophthalmology and Visual Science, College of Medicine, Seoul St. Mary’s Hospital, The Catholic University of Korea, Seoul, Korea
| | - Chan Kee Park
- Department of Ophthalmology and Visual Science, College of Medicine, Seoul St. Mary’s Hospital, The Catholic University of Korea, Seoul, Korea
| |
Collapse
|
8
|
Fang L, Turtschi S, Mozaffarieh M. The effect of nifedipine on retinal venous pressure of glaucoma patients with the Flammer-Syndrome. Graefes Arch Clin Exp Ophthalmol 2015; 253:935-9. [PMID: 25863672 DOI: 10.1007/s00417-015-3001-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2014] [Revised: 03/17/2015] [Accepted: 03/25/2015] [Indexed: 01/04/2023] Open
Abstract
PURPOSE The purpose was to measure the retinal venous pressure (RVP) in both eyes of primary open-angle glaucoma (POAG) patients before and 3 weeks after treatment with low-dosed Nifedipine. METHODS This retrospective study included 20 POAG patients who were treated with Nifedipine (5 mg daily) and 20 untreated control POAG patients. In both the treated and untreated control group, a distinction was made between those patients who had the Flammer-Syndrome (FS) and those who did not. The RVP was measured in all patients bilaterally at baseline and 3 weeks later by means of contact lens ophthalmodynamometry and the RVP measurements of the treated POAG patients were compared to the RVPs of the untreated POAG controls. Ophthalmodynamometry is done by applying an increasing force on the eye via a contact lens. The minimum force required to induce a venous pulsation is called the ophthalmodynamometric force (ODF). The RVP is defined and calculated as the sum of ODF and intraocular pressure (IOP) [RVP = ODF + IOP]. RESULTS The RVP decreased significantly after 3 weeks in both eyes of patients treated with low-dosed Nifedipine compared to the untreated group (mean decrease of 12.5 mmHg (SD 12.5), P < 0.001). A larger response to therapy was found in patients with the FS compared to patients lacking the FS (mean decrease of 16.07 vs. 7.28 mmHg, confidence Interval (CI): 5.2 to 9.3 vs. 12.3 to 19.7; P < 0.001). No significant differences were accounted for in the IOP's of the patients after treatment. In the untreated control group, no significant differences were accounted for either in the RVP or the IOP after 3 weeks. CONCLUSIONS Treatment with low-dosed Nifedipine decreases RVP in both eyes of glaucoma patients, particularly in those with the Flammer-Syndrome. This effect may be due to the partial inhibition of Endothelin-1 (ET-1) by Nifedipine.
Collapse
Affiliation(s)
- L Fang
- Department of Ophthalmology, University of Basel, Mittlere Strasse 91, 4031, Basel, Switzerland
| | | | | |
Collapse
|
9
|
Samarai V, Sharifi N, Nateghi S. Association between helicobacter pylori infection and primary open angle glaucoma. Glob J Health Sci 2014; 6:13-7. [PMID: 25363173 PMCID: PMC4796414 DOI: 10.5539/gjhs.v6n7p13] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2014] [Revised: 08/11/2014] [Accepted: 07/28/2014] [Indexed: 01/06/2023] Open
Abstract
Aim: To compare the prevalence of Pylori infection in patients with primary open angle glaucoma (POAG) and control group with cataract. Methods: This is a prospective case-control study. The participants were organized in two groups. First group (case) consisted of 35 patients with POAG and second group consisted of 35 age matched participants with cataract whose optic disk could be evaluated. Serum levels of anti H. pylori IgG antibody were evaluated with the method of ELISA. Results: The seroprevalence of Pylori infection was 89.1 % (33 of 37) in patients with POAG and 59.5 % (25 of 42) in the control group. The difference was significant (P=0.008). The odds ratio for association between Pylori and POAG was 5.69 and the range of 95% confidence interval was from 1.58 to 20.50. Conclusion: This study suggests that Helicobacter Pylori infection might be associated with primary open angle glaucoma.
Collapse
|
10
|
Ster AM, Popp RA, Petrisor FM, Stan C, Pop VI. The Role of Oxidative Stress and Vascular Insufficiency in Primary Open Angle Glaucoma. ACTA ACUST UNITED AC 2014; 87:143-6. [PMID: 26528013 PMCID: PMC4508597 DOI: 10.15386/cjmed-295] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2014] [Revised: 08/28/2014] [Accepted: 08/15/2014] [Indexed: 11/24/2022]
Abstract
Primary Open Angle Glaucoma (POAG) is a chronic, irreversible optic neuropathy leading to the progressive death of retinal ganglion cells, clinically observed as silent visual field loss along with a decrease in colour and contrast sensitivity. Multiple pathogenic theories have been issued and some of them have proven their involvement in disease development: mechanical damage due to increased intraocular pressure, variable susceptibility of the optic nerve, mutation in specific nuclear genes, increased glutamate levels, alteration in nitric oxide (NO) metabolism, changes in the mitochondrial genome, vascular disturbances, and toxic effects and oxidative damage caused by reactive oxygen species [1]. The aim of this article is to highlight the pathogenic role of vascular disturbances and reactive oxygen species in POAG with the further possibilities for prevention and gene therapy.
Collapse
Affiliation(s)
- Anda Maria Ster
- Dept. of Ophthalmology, Iuliu Hatieganu University of Medicine and Pharmacy, Cluj-Napoca, Romania
| | - Radu Anghel Popp
- Dept. of Medical Genetics, Iuliu Hatieganu University of Medicine and Pharmacy, Cluj-Napoca, Romania
| | - Felicia Maria Petrisor
- Dept. of Medical Genetics, Iuliu Hatieganu University of Medicine and Pharmacy, Cluj-Napoca, Romania
| | - Cristina Stan
- Dept. of Ophthalmology, Iuliu Hatieganu University of Medicine and Pharmacy, Cluj-Napoca, Romania
| | - Victor Ioan Pop
- Dept. of Medical Genetics, Iuliu Hatieganu University of Medicine and Pharmacy, Cluj-Napoca, Romania
| |
Collapse
|
11
|
Mozaffarieh M, Konieczka K, Flammer J. Calcium channel blockers: their use in normal tension glaucoma. EXPERT REVIEW OF OPHTHALMOLOGY 2014. [DOI: 10.1586/eop.10.54] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
|
12
|
Flammer J, Konieczka K, Flammer AJ. The primary vascular dysregulation syndrome: implications for eye diseases. EPMA J 2013; 4:14. [PMID: 23742177 PMCID: PMC3693953 DOI: 10.1186/1878-5085-4-14] [Citation(s) in RCA: 196] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Accepted: 04/26/2013] [Indexed: 01/08/2023]
Abstract
Vascular dysregulation refers to the regulation of blood flow that is not adapted to the needs of the respective tissue. We distinguish primary vascular dysregulation (PVD, formerly called vasospastic syndrome) and secondary vascular dysregulation (SVD). Subjects with PVD tend to have cold extremities, low blood pressure, reduced feeling of thirst, altered drug sensitivity, increased pain sensitivity, prolonged sleep onset time, altered gene expression in the lymphocytes, signs of oxidative stress, slightly increased endothelin-1 plasma level, low body mass index and often diffuse and fluctuating visual field defects. Coldness, emotional or mechanical stress and starving can provoke symptoms. Virtually all organs, particularly the eye, can be involved. In subjects with PVD, retinal vessels are stiffer and more irregular, and both neurovascular coupling and autoregulation capacity are reduced while retinal venous pressure is often increased. Subjects with PVD have increased risk for normal-tension glaucoma, optic nerve compartment syndrome, central serous choroidopathy, Susac syndrome, retinal artery and vein occlusions and anterior ischaemic neuropathy without atherosclerosis. Further characteristics are their weaker blood–brain and blood-retinal barriers and the higher prevalence of optic disc haemorrhages and activated astrocytes. Subjects with PVD tend to suffer more often from tinnitus, muscle cramps, migraine with aura and silent myocardial ischaemic and are at greater risk for altitude sickness. While the main cause of vascular dysregulation is vascular endotheliopathy, dysfunction of the autonomic nervous system is also involved. In contrast, SVD occurs in the context of other diseases such as multiple sclerosis, retrobulbar neuritis, rheumatoid arthritis, fibromyalgia and giant cell arteritis. Taking into consideration the high prevalence of PVD in the population and potentially linked pathologies, in the current article, the authors provide recommendations on how to effectively promote the field in order to create innovative diagnostic tools to predict the pathology and develop more efficient treatment approaches tailored to the person.
Collapse
Affiliation(s)
- Josef Flammer
- Department of Ophthalmology, University of Basel, Mittlere Strasse 91, Basel CH-4031, Switzerland.
| | | | | |
Collapse
|
13
|
Abstract
The vasculature of the eye and the heart share several common characteristics. The easily accessible vessels of the eye are therefore-to some extent-a window to the heart. There is interplay between cardiovascular functions and risk factors and the occurrence and progression of many eye diseases. In particular, arteriovenous nipping, narrowing of retinal arteries, and the dilatation of retinal veins are important signs of increased cardiovascular risk. The pressure in the dilated veins is often markedly increased due to a dysregulation of venous outflow from the eye. Besides such morphological criteria, functional alterations might be even more relevant and may play an important role in future diagnostics. Via neurovascular coupling, flickering light dilates capillaries and small arterioles, thus inducing endothelium-dependent, flow-mediated dilation of larger retinal vessels. Risk factors for arteriosclerosis, such as dyslipidaemia, diabetes, or systemic hypertension, are also risk factors for eye diseases such as retinal arterial or retinal vein occlusions, cataracts, age-related macular degeneration, and increases in intraocular pressure (IOP). Functional alterations of blood flow are particularly relevant to the eye. The primary vascular dysregulation syndrome (PVD), which often includes systemic hypotension, is associated with disturbed autoregulation of ocular blood flow (OBF). Fluctuation of IOP on a high level or blood pressure on a low level leads to instable OBF and oxygen supply and therefore to oxidative stress, which is particularly involved in the pathogenesis of glaucomatous neuropathy. Vascular dysregulation also leads to a barrier dysfunction and thereby to small retinal haemorrhages.
Collapse
Affiliation(s)
- Josef Flammer
- Department of Ophthalmology, University of Basel, Mittlere Strasse 91, Basel 4031, Switzerland.
| | | | | | | | | | | |
Collapse
|
14
|
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.
Collapse
Affiliation(s)
- Danny Moore
- Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, IN, USA
| | | | | | | | | |
Collapse
|
15
|
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.
Collapse
Affiliation(s)
- Gilbert T Feke
- Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, MA 02114, USA
| | | | | | | |
Collapse
|
16
|
Abstract
Glaucoma is a neurodegenerative disease characterized by loss of retinal ganglion cells and their axons. Recent evidence suggests that intraocular pressure (IOP) is only one of the many risk factors for this disease. Current treatment options for this disease have been limited to the reduction of IOP; however, it is clear now that the disease progression continues in many patients despite effective lowering of IOP. In the search for newer modalities in treating this disease, much data have emerged from experimental research the world over, suggesting various pathological processes involved in this disease and newer possible strategies to treat it. This review article looks into the current understanding of the pathophysiology of glaucoma, the importance of neuroprotection, the various possible pharmacological approaches for neuroprotection and evidence of current available medications.
Collapse
Affiliation(s)
- Sushil K Vasudevan
- Centre for Eye Research Australia, University of Melbourne and Glaucoma Unit, Royal Victorian Eye and Ear Hospital, East Melbourne, VIC 3002, Australia.
| | | | | |
Collapse
|
17
|
Fraenkl SA, Mozaffarieh M, Flammer J. Retinal vein occlusions: The potential impact of a dysregulation of the retinal veins. EPMA J 2010; 1:253-261. [PMID: 21258633 PMCID: PMC3003793 DOI: 10.1007/s13167-010-0025-2] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2010] [Accepted: 05/19/2010] [Indexed: 12/29/2022]
Abstract
A retinal vein occlusion (RVO) is a sight threatening disease. It can be divided into central vein occlusion and branch retinal vein occlusion. The pathogenesis of the condition remains to be solved. Mechanical compression of the vessel wall or thrombotic occlusion of the vessel lumen, sometimes combined with rheological disorders, are often assumed pathomechanisms. Accordingly, the therapy relies either on mechanical decompression, lyses of thrombi or improvement of rheology. A number of observations however, such as the relationship of RVO to atherosclerotic risk factors, spontaneous reversibility particularly in young patients, rest flow observed in angiography, occlusion despite anticoagulation or thrombocytopenia and finally the positive effect of anti-VEGF therapy are not explained by the present pathogenetic concept. As a new concept we propose a local venous constriction induced by vasoconstrictive molecules diffusing from neighbouring diseased arteries and/or from other neighbouring (hypoxic) tissues. Recognizing these postulated conditions might lead to an earlier identification of impending vein occlusions as well as to a treatment more tailored to the risk factor constellation of the particular patient.
Collapse
Affiliation(s)
- Stephan A Fraenkl
- Department of Ophthalmology, University of Basel, Mittlere Strasse 91, 4031 Basel, Switzerland
| | | | | |
Collapse
|
18
|
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.
Collapse
|
19
|
Kunimatsu S, Mayama C, Tomidokoro A, Araie M. Plasma Endothelin-1 Level in Japanese Normal Tension Glaucoma Patients. Curr Eye Res 2009; 31:727-31. [PMID: 16966145 DOI: 10.1080/02713680600837382] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
PURPOSE To compare the plasma concentration of endothelin-1 (ET-1) among patients < 60 years of age with normal-tension glaucoma (NTG), primary open-angle glaucoma (POAG), and in age-matched normal participants. METHODS Plasma concentration of ET-1 was determined in 30 NTG 18 POAG patients, and 19 age-matched normal participants using an enzyme immunoassay. RESULTS The ET-1 level was 1.49 +/- 0.51 pg/ml in the NTG patients (49.4 +/- 8.8 years), 1.58 +/- 0.64 pg/ml in the POAG patients (44.7 +/- 10.7 years), and 1.33 +/- 0.50 pg/ml in the normal participants (49.9 +/- 5.6 years). The ET-1 levels were not significantly different among the three groups, and no significant correlation with the extent of visual field damage, intraocular pressure (IOP), refraction, or age was seen in the glaucoma patients. CONCLUSIONS The plasma ET-1 level showed no difference among NTG patients, POAG patients, and normal participants < 60 years of age in the Japanese population.
Collapse
Affiliation(s)
- Shiho Kunimatsu
- Department of Ophthalmology, University of Tokyo Graduate School of Medicine, Tokyo, Japan
| | | | | | | |
Collapse
|
20
|
Agarwal R, Gupta SK, Agarwal P, Saxena R, Agrawal SS. Current concepts in the pathophysiology of glaucoma. Indian J Ophthalmol 2009; 57:257-66. [PMID: 19574692 PMCID: PMC2712693 DOI: 10.4103/0301-4738.53049] [Citation(s) in RCA: 124] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2007] [Accepted: 05/26/2008] [Indexed: 11/13/2022] Open
Abstract
Glaucoma, the second leading cause of blindness, is characterized by changes in the optic disc and visual field defects. The elevated intraocular pressure was considered the prime factor responsible for the glaucomatous optic neuropathy involving death of retinal ganglion cells and their axons. Extensive investigations into the pathophysiology of glaucoma now reveal the role of multiple factors in the development of retinal ganglion cell death. A better understanding of the pathophysiological mechanisms involved in the onset and progression of glaucomatous optic neuropathy is crucial in the development of better therapeutic options. This review is an effort to summarize the current concepts in the pathophysiology of glaucoma so that newer therapeutic targets can be recognized. The literature available in the National Medical Library and online Pubmed search engine was used for literature review.
Collapse
Affiliation(s)
- Renu Agarwal
- Department of Ocular Pharmacology, Delhi Institute of Pharmaceutical Sciences and Research, New Delhi, India
| | - Suresh K Gupta
- Department of Ocular Pharmacology, Delhi Institute of Pharmaceutical Sciences and Research, New Delhi, India
| | - Puneet Agarwal
- Department of Ocular Pharmacology, Delhi Institute of Pharmaceutical Sciences and Research, New Delhi, India
| | - Rohit Saxena
- Dr. Rajendra Prasad Center for Ophthalmic Sciences, New Delhi, India
| | - Shyam S Agrawal
- Department of Ocular Pharmacology, Delhi Institute of Pharmaceutical Sciences and Research, New Delhi, India
| |
Collapse
|
21
|
Abstract
Glaucoma is a group of ocular diseases characterized by optic neuropathy associated with loss of the retinal nerve fibre layer and re-modelling of the optic nerve head, and a subsequent particular pattern of visual field loss. Increased intraocular pressure is the most important risk factor for the disease, but the pathogenesis of glaucoma is not monofactorial. Among other factors, ischaemia and vascular dysregulation have been implicated in the mechanisms underlying glaucoma. The vascular endothelium plays an important role in the regulation of ocular blood flow and pathological alterations of vascular endothelial cells may induce ischaemia and dysregulation. The present review summarizes our current evidence of endothelial dysfunction in glaucoma. This is of interest because endothelial dysfunction is a good prognostic factor for progression in several diseases. Although such data are lacking for glaucoma, endothelial dysfunction may provide an attractive target for therapeutic intervention in open-angle glaucoma and other vascular disorders of the eye.
Collapse
Affiliation(s)
- Hemma Resch
- Department of Clinical Pharmacology, Medical University, Vienna, Austria
| | | | | | | | | |
Collapse
|
22
|
Flammer J, Mozaffarieh M. Autoregulation, a balancing act between supply and demand. Can J Ophthalmol 2008; 43:317-21. [DOI: 10.3129/i08-056] [Citation(s) in RCA: 114] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
|
23
|
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.
Collapse
Affiliation(s)
- Gilbert T Feke
- Schepens Retina Associates Foundation, Boston, Massachusetts 02215, USA.
| | | |
Collapse
|
24
|
Jeoung JW, Kim DM, Ko HS, Park SS, Kim JY, Kim SY, Yoo TW. Investigation of the association between normal-tension glaucoma and single nucleotide polymorphisms in natriuretic peptide gene. KOREAN JOURNAL OF OPHTHALMOLOGY 2007; 21:33-8. [PMID: 17460430 PMCID: PMC2629695 DOI: 10.3341/kjo.2007.21.1.33] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Purpose The expression of natriuretic peptides in the neural bundles of the anterior portion of the optic nerves and their functions in regulating vessel tone and blood flow may suggest a possible role in the pathogenesis of glaucoma. The purpose of this study was to investigate the association between normal-tension glaucoma and the genetic variations of atrial natriuretic peptide (Nppa) and natriuretic peptide receptor A (Npr1) gene. Methods Sixty-seven Korean normal-tension glaucoma (NTG) patients and 100 healthy subjects (as normal controls) were enrolled. DNA from peripheral blood leukocytes was extracted, and the genotypes of five polymorphisms (c.94G>A, c.454T>C, IVS1+16C>T, IVS2+701G>A, and c.-764C>G) in the Nppa gene and one polymorphism (c.1023G>C) in the Npr1 gene were determined using the restriction fragment length polymorphism and the SNaPshot methods. The genotype and allele frequencies of these polymorphisms in patients with NTG and normal controls were compared using the Fisher's exact test and the chi-square test. Results In both groups, the genotype distributions were in accordance with the Hardy-Weinberg equilibrium. There was no significant difference in the frequency of the Nppa and Npr1 alleles or genotypes in the normal-tension glaucoma group as compared to the control group. Conclusions Nppa and Npr1 gene polymorphisms are not associated with normal-tension glaucoma, suggesting that this gene does not have an important role in the pathogenesis of optic neuropathy in this disease.
Collapse
Affiliation(s)
- Jin Wook Jeoung
- Department of Ophthalmology, Seoul National University Hospital, Seoul, Korea
- Seoul National University Hospital Clinical Research Institute, Seoul, Korea
| | - Dong Myung Kim
- Department of Ophthalmology, Seoul National University Hospital, Seoul, Korea
- Seoul National University Hospital Clinical Research Institute, Seoul, Korea
| | - Hyun Soo Ko
- Department of Laboratory Medicine, Seoul National University Hospital, Seoul, Korea
- Seoul National University Hospital Clinical Research Institute, Seoul, Korea
| | - Sung Sup Park
- Department of Laboratory Medicine, Seoul National University Hospital, Seoul, Korea
- Seoul National University Hospital Clinical Research Institute, Seoul, Korea
| | - Ji Yeon Kim
- Department of Laboratory Medicine, Seoul National University Hospital, Seoul, Korea
- Seoul National University Hospital Clinical Research Institute, Seoul, Korea
| | - Sung Yeun Kim
- Department of Laboratory Medicine, Seoul National University Hospital, Seoul, Korea
- Seoul National University Hospital Clinical Research Institute, Seoul, Korea
| | - Tai Woo Yoo
- Department of Family Medicine, Seoul National University Hospital, Seoul, Korea
| |
Collapse
|
25
|
Abstract
During the last decade, the presumed etiology of glaucoma has moved from a pure pressure concept to a combined mechanical and vascular theory. Evidence of a localized vascular insufficiency leading to perfusion deficits of ocular structures, including the optic nerve head, the retina, the choroid, and the retrobulbar vessels, is now clear. This article evaluates the role of vasospasm as the primary cause of such a vascular failure. The role of both ocular and systemic vasospasms and their clinical correlations are discussed. At a cellular level, the function of the modulating role of the vascular endothelium is reviewed. Evidence of abnormalities of the vascular endothelium and its vasoactive peptides as a conduit for vasospasm is mounting. Herein lies exciting prospects for potential pharmacologic targets in future glaucoma management.
Collapse
|
26
|
Pache M, Flammer J. A Sick Eye in a Sick Body? Systemic Findings in Patients with Primary Open-angle Glaucoma. Surv Ophthalmol 2006; 51:179-212. [PMID: 16644363 DOI: 10.1016/j.survophthal.2006.02.008] [Citation(s) in RCA: 118] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Despite intense research, the pathogenesis of primary open-angle glaucoma (POAG) is still not completely understood. There is ample evidence for a pathophysiological role of elevated intraocular pressure; however, several systemic factors may influence onset and progression of the disease. Systemic peculiarities found in POAG include alterations of the cardiovascular system, autonomic nervous system, immune system, as well as endocrinological, psychological, and sleep disturbances. An association between POAG and other neurodegenerative diseases, such as Alzheimer disease and Parkinson disease, has also been described. Furthermore, the diagnosis of glaucoma can affect the patient's quality of life. By highlighting the systemic alterations found in POAG, this review attempts to bring glaucoma into a broader medical context.
Collapse
|
27
|
Ohguro I, Ohguro H, Ohta T, Nakazawa M. A case of normal tension glaucoma associated with Buerger's disease. TOHOKU J EXP MED 2006; 209:49-52. [PMID: 16636522 DOI: 10.1620/tjem.209.49] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Open angle glaucoma, a slowly progressive optic atrophy, is clinically characterized by visual field defects corresponding to excavation of the optic disc, called glaucomatous cupping. Open angle glaucoma is further divided into primary open angle glaucoma caused by elevated intraocular pressure (higher than the normal limit of 21 mmHg), and normal tension glaucoma, in which intraocular pressure is in the normal range. Here we report a case of normal tension glaucoma associated with Buerger's disease, also known as thromboangiitis obliterans, which causes systemic blood flow disturbance. A 66-year-old man suffering from Buerger's disease for 10 years was diagnosed as having branch retinal artery occlusion in his left eye. He was referred to our clinic due to progressive visual field disturbance in that eye. Ophthalmologic examinations revealed occlusion in the infero-temporal retinal artery in the left eye, and glaucomatous cupping, normal intraocular pressure, retinal vessel tortuosity and retinal arteriosclerosis in both eyes. Visual field examination revealed decreased retinal sensitivities in the areas within the visual field arches above and below fixation from the blind spot to the median raphe, corresponding to the arcuate retinal nerve fibers comprising the Bjerrum areas and the area corresponding to the retinal artery occlusion. Buerger's disease is characterized by the development of segmental thrombotic occlusions and vasospasm of the medium and small arteries. Our case suggests that the blood flow disturbance due to arteriosclerosis, thrombotic occlusions and vasospasm associated with Buerger's disease might affect the ophthalmic circulation system, thereby contributing to the etiology of normal tension glaucoma.
Collapse
Affiliation(s)
- Ikuyo Ohguro
- Department of Ophthalmology, Hirosaki Medical University School of Medicine, 5 Zaifu-cho, Hirosaki 036-8562, Japan.
| | | | | | | |
Collapse
|
28
|
Emre M, Orgül S, Haufschild T, Shaw SG, Flammer J. Increased plasma endothelin-1 levels in patients with progressive open angle glaucoma. Br J Ophthalmol 2005; 89:60-3. [PMID: 15615748 PMCID: PMC1772488 DOI: 10.1136/bjo.2004.046755] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
AIM To compare the plasma levels of endothelin-1 (ET-1) between patients with primary open angle glaucoma with visual field progression despite normal or normalised intraocular pressure and patients with stabile visual fields in a retrospective study. METHODS The progressive group consisted of 16 primary open angle glaucoma patients and the group with stable visual field consisted of 15 patients. After a 30 minute rest in a supine position, venous blood was obtained for ET-1 dosing. Difference in the plasma level of ET-1 between two groups was compared by means of analysis of covariance (ANCOVA), including age, sex, and mean arterial blood pressure as covariates. RESULTS ET-1 plasma levels were found to be significantly increased in patients with deteriorating (3.47 (SD 0.75) pg/ml) glaucoma when compared to those with stable (2.59 (SD 0.54) pg/ml) visual fields (p = 0.0007). CONCLUSIONS Glaucoma patients with visual field progression in spite of normal or normalised intraocular pressure have been found to have increased plasma endothelin-1 levels. It remains to be determined if this is a secondary phenomenon or whether it may have a role in the progression of glaucomatous damage.
Collapse
Affiliation(s)
- M Emre
- University Eye Clinic Basel, Mittlere Strasse 91, PO Box, 4012 Basel, Switzerland
| | | | | | | | | |
Collapse
|
29
|
Polak K, Luksch A, Frank B, Jandrasits K, Polska E, Schmetterer L. Regulation of human retinal blood flow by endothelin-1. Exp Eye Res 2003; 76:633-40. [PMID: 12697427 DOI: 10.1016/s0014-4835(02)00312-3] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
There is evidence from in vitro and animal studies that endothelin is a major regulator of retinal blood flow. We set out to characterize the role of the endothelin-system in the blood flow control of the human retina. Two studies in healthy subjects were performed. The study design was randomized, placebo-controlled, double-masked, balanced, two-way crossover in protocol A and three way-way crossover in protocol B. In protocol A 18 healthy male subjects received intravenous endothelin-1 (ET-1) in a dose of 2.5 ng kg (-1)min(-1) for 30 min or placebo on two different study days and retinal vessel diameters were measured. In protocol B 12 healthy male subjects received ET-1 in stepwise increasing doses of 0, 1.25, 2.5 and 5 ng kg (-1)min(-1) (each infusion step over 20 min) in co-infusion with the specific ET(A)-receptor antagonist BQ123 (60 microg min (-1)) or placebo or BQ123 alone investigating retinal vessel diameters, retinal blood velocity and retinal blood flow. Measurements of retinal vessel size were done with the Zeiss retinal vessel analyzer. Measurements of blood velocities were done with bi-directional laser Doppler velocimetry. From these measurements retinal blood flow was calculated. In protocol A exogenous ET-1 tended to decrease retinal arterial diameter, but this effect was not significant versus placebo. No effect on retinal venous diameter was seen. In protocol B retinal venous blood velocity and retinal blood flow was significantly reduced after administration of exogenous ET-1. These effects were significantly blunted when BQ-123 was co-administered. By contrast, BQ-123 alone had no effect on retinal hemodynamic parameters. Concluding, BQ123 antagonizes the effects of exogenously administered ET-1 on retinal blood flow in healthy subjects. In addition, the results of the present study are compatible with the hypothesis that ET-1 exerts its vasoconstrictor effects in the retina mainly on the microvessels.
Collapse
Affiliation(s)
- Kaija Polak
- Department of Clinical Pharmacology, Vienna General Hospital, University of Vienna, Währinger Gürtel 18-20, Vienna 1090, Austria
| | | | | | | | | | | |
Collapse
|
30
|
Abstract
Endothelin is a vasoactive peptide that has been shown to play an important role in vascular homeostasis. Recently, endothelin and its receptors have been found in ocular tissues where it appears to have a regulatory function. Endothelin is found in both the aqueous and vitreous humors and its concentration is elevated in glaucoma patients and in animal models of glaucoma. In the current review, the authors present information about the distribution of endothelin and endothelin receptors in the eye and the ocular actions of endothelins. Specifically, endothelin/aqueous humor dynamics, endothelin/nitric oxide interactions, endothelin and ischemia, and endothelin/optic nerve head effects. Observations concerning the potential role of endothelin in glaucoma pathophysiology is presented and discussed relative to its effects on the optic nerve head and in relation to glaucoma theories.
Collapse
Affiliation(s)
- Thomas Yorio
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, North Texas Eye Research Institute, Fort Worth, Texas 76107, USA.
| | | | | |
Collapse
|
31
|
Harris A, Jonescu-Cuypers C, Martin B, Kagemann L, Zalish M, Garzozi HJ. Simultaneous management of blood flow and IOP in glaucoma. ACTA OPHTHALMOLOGICA SCANDINAVICA 2001; 79:336-41. [PMID: 11453850 DOI: 10.1034/j.1600-0420.2001.079004336.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Factors other than intraocular pressure (IOP) elevation must be involved in initiation and progression of glaucoma. An additional element in disease causation may be ischemia in the retina and optic nerve head. Ischemic damage to neurons in the CNS is similar mechanistically and histopathologically to changes seen in glaucoma. Further, glaucoma patients with normal IOP show clear evidence for cerebral and ocular ischemia. Aging and atherosclerosis reduce the ability of the eye to autoregulate blood flow when ocular perfusion pressure changes: the dependence of blood flow on perfusion pressure links ischemia to IOP. Consequently, neuroprotective treatments for glaucoma should be designed to both reduce IOP and improve ocular nutrient delivery.
Collapse
Affiliation(s)
- A Harris
- Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, IN 46202-5175, USA.
| | | | | | | | | | | |
Collapse
|
32
|
Cioffi GA. Three Common Assumptions About Ocular Blood Flow and Glaucoma. Surv Ophthalmol 2001; 45 Suppl 3:S325-31; discussion S332-4. [PMID: 11377457 DOI: 10.1016/s0039-6257(01)00199-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Although substantial indirect evidence exists to link altered ocular blood flow to glaucoma, it must be remembered that the validity of investigations in this area depends on acceptance of three basic assumptions: 1) ischemia directly causes or increases the susceptibility of the optic nerve to glaucomatous damage; 2) optic nerve vascular anatomy and physiology allows identification of the critical vascular beds in optic nerve disease; and 3) current measurement techniques provide the ability to monitor important vascular beds. The hypotheses underlying these assumptions are examined.
Collapse
Affiliation(s)
- G A Cioffi
- Discoveries in Sight, Devers Eye Institute, Portland, OR 97210, USA
| |
Collapse
|
33
|
Flammer J, Pache M, Resink T. Vasospasm, its role in the pathogenesis of diseases with particular reference to the eye. Prog Retin Eye Res 2001; 20:319-49. [PMID: 11286896 DOI: 10.1016/s1350-9462(00)00028-8] [Citation(s) in RCA: 255] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Vasospasm can have many different causes and can occur in a variety of diseases, including infectious, autoimmune, and ophthalmic diseases, as well as in otherwise healthy subjects. We distinguish between the primary vasospastic syndrome and secondary vasospasm. The term "vasospastic syndrome" summarizes the symptoms of patients having such a diathesis as responding with spasm to stimuli like cold or emotional stress. Secondary vasospasm can occur in a number of autoimmune diseases, such as multiple sclerosis, lupus erythematosus, antiphospholipid syndrome, rheumatoid polyarthritis, giant cell arteritis, Behcet's disease, Buerger's disease and preeclampsia, and also in infectious diseases such as AIDS. Other potential causes for vasospasm are hemorrhages, homocysteinemia, head injury, acute intermittent porphyria, sickle cell disease, anorexia nervosa, Susac syndrome, mitochondriopathies, tumors, colitis ulcerosa, Crohn's disease, arteriosclerosis and drugs. Patients with primary vasospastic syndrome tend to suffer from cold hands, low blood pressure, and even migraine and silent myocardial ischemia. Valuable diagnostic tools for vasospastic diathesis are nailfold capillary microscopy and angiography, but probably the best indicator is an increased plasma level of endothelin-1. The eye is frequently involved in the vasospastic syndrome, and ocular manifestations of vasospasm include alteration of conjunctival vessels, corneal edema, retinal arterial and venous occlusions, choroidal ischemia, amaurosis fugax, AION, and glaucoma. Since the clinical impact of vascular dysregulation has only really been appreciated in the last few years, there has been little research in the according therapeutic field. The role of calcium channel blockers, magnesium, endothelin and glutamate antagonists, and gene therapy are discussed.
Collapse
Affiliation(s)
- J Flammer
- University Eye Clinic Basel, Mittlere Strasse 91, CH-4012, Basel, Switzerland.
| | | | | |
Collapse
|
34
|
Matsumoto M, Matsuhashi H, Nakazawa M. Normal tension glaucoma and primary open angle glaucoma associated with increased platelet aggregation. TOHOKU J EXP MED 2001; 193:293-9. [PMID: 11453537 DOI: 10.1620/tjem.193.293] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
On purpose of the present study was to evaluate platelet aggregation and fibrinolytic systems in patients with normal tension glaucoma (NTG) or primary open angle glaucoma (POAG). For platelet aggregation, we photoelectrophotometrically investigated adenosine diphosphate (ADP) or collagen-induced platelet aggregation in consecutively selected patients with glaucoma (22 patients with NTG and 13 patients with POAG) and 42 glaucoma free control subjects with normal ocular findings. The aggregation patterns of the patients' platelets reacted abnormally to ADP 1 microM or collagen 0.5 microg/ml as evidenced by secondary aggregation were compared with those of control subjects. For blood coagulative and fibrinolytic systems, we measured prothrombin time, activated partial thromboplastin time, fibrinogen, thrombin-antithrombin III complex (TAT), alpha2 plasmin inhibitor-plasmin complex. Seventeen of 22 patients (77%) with NTG and 5 of 13 patients (38%) with POAG showed abnormal secondary aggregation. A significant difference was observed between the two groups. No control subjects showed abnormal secondary aggregation. In the fibrinolytic test, all the parameters examined showed within normal ranges, although the log10(TAT) value was higher in NTG than in POAG. Results of the present study suggested that increased platelet aggregation as defined by ADP or collagen induced abnormal secondary aggregation in vitro is frequently associated with glaucoma patients and this tendency is more apparent in NTG than that in POAG.
Collapse
Affiliation(s)
- M Matsumoto
- Department of Ophthalmology, Hirosaki University School of Medicine, Japan.
| | | | | |
Collapse
|
35
|
Kountouras J, Mylopoulos N, Boura P, Bessas C, Chatzopoulos D, Venizelos J, Zavos C. Relationship between Helicobacter pylori infection and glaucoma. Ophthalmology 2001; 108:599-604. [PMID: 11237916 DOI: 10.1016/s0161-6420(00)00598-4] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
OBJECTIVE To determine the frequency of Helicobacter pylori (H. pylori) infection in glaucoma patients and in anemic control participants. DESIGN Prospective, nonrandomized, comparative study. PARTICIPANTS The authors investigated 32 patients with chronic open-angle glaucoma (COAG), 9 patients with pseudoexfoliation glaucoma (PEG), and 30 age-matched anemic control participants. METHODS Upper gastrointestinal endoscopy was performed to evaluate macroscopic abnormalities, and gastric mucosal biopsy specimens were obtained for the presence of H. pylori infection tested by rapid urease slide test (CLO test) and by Cresyl fast violet staining, Giemsa staining, or both. The presence of gastritis was classified in accordance with the Sydney system by using hematoxylin and eosin stain. In addition, intestinal metaplasia was evaluated with Alcian blue stain. Saliva samples were also tested by CLO. Serum was analyzed for the presence of H. pylori-specific IgG antibodies by enzyme-linked immunosorbent assay. MAIN OUTCOME MEASURE Histologic examination for the presence of H. pylori. RESULTS In 87.5% of the COAG patients, 88.9% of the PEG patients, and 46.7% of the anemic control participants, H. pylori infection was histologically confirmed (odds ratio, 8.00; chi-square, 11.81; P = 0.0006 and 9.14; chi-square, 5.01; P = 0.02, respectively). H. pylori was detected by urease test: (1) in the gastric mucosa in 71.9% of the COAG patients, in 77.8% of the PEG patients, and in 46.7% of the anemic control participants (P = 0.03 and P > 0.05, respectively); and (2) in the saliva in 37.5% of the COAG patients, in 55.6% of the PEG patients, and in 30% of the anemic control participants (P > 0.05). Sixty-eight percent of glaucoma patients and 30% of anemic control participants were seropositive for H. pylori (P = 0.002). When compared with anemic control participants, glaucoma patients exhibited less often endoscopic normal appearance of gastric mucosa (P = 0.01), and more often antral gastritis (P = 0.0004) or peptic ulcer disease (P = 0.01). Histologic grade 3 gastritis was observed only in the glaucoma patients (P = 0.03). CONCLUSIONS H. pylori infection seems more frequent in glaucoma patients. If confirmed, this may indicate either a common factor that causes susceptibilities to both glaucoma and H. pylori infection or that H. pylori may be a causal factor for developing glaucoma.
Collapse
Affiliation(s)
- J Kountouras
- Department of Medicine, Second Medical Clinic, Aristotle University of Thessaloniki, Ippokration Hospital, Thessaloniki, Greece.
| | | | | | | | | | | | | |
Collapse
|
36
|
Gugleta K, Orgül S, Stümpfig D, Dubler B, Flammer J. Fludrocortisone in the treatment of systemic hypotension in primary open-angle glaucoma patients. Int Ophthalmol 2001; 23:25-30. [PMID: 11008895 DOI: 10.1023/a:1006434231844] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
BACKGROUND Fludrocortisone is a potent mineralocorticoid, which has no known direct vasoactive properties, and is the first-line drug for treatment of orthostatic hypotension. The present study evaluated the systemic hemodynamic effects of fludrocortisone treatment in glaucoma patients. PATIENTS AND METHODS A retrospective analysis of the charts of glaucoma patients of the University Eye-Clinic Basel was performed. Twenty-two patients with open-angle glaucoma under treatment with fludrocortisone were selected. The selected patients had one 24-h blood pressure recording immediately prior to treatment with fludrocortisone and one recording at least 2 months after starting the treatment. Parallel to blood pressure recordings, diurnal intraocular tension curve recordings and visual field testings were carried out. In addition, twelve patients also had nail-fold video-capillaroscopy. RESULTS IOP and visual fields remained stable. The average values for all systemic blood-pressure readings showed an improvement in the follow-up compared to primary examination. Mean (+/- SD) night-to-day ratio ('nocturnal dips') of systolic, diastolic and mean arterial blood pressure decreased from 13.6 +/- 4.3%, 16.9 +/- 5.2% and 15.9 +/- 3.5%, respectively, to 9.9 +/- 5.9% (p = 0.01), 13.2 +/- 4.3% (p = 0.044) and 11.7 +/- 3.9% (p = 0.0004). Baseline capillary blood-flow velocity increased and capillary blood-flow standstill time after cold provocation decreased significantly under fludrocortisone therapy. CONCLUSION Hemodynamic parameters show a tendency towards improvement in a magnitude which might be of clinical relevance.
Collapse
Affiliation(s)
- K Gugleta
- University Eye Clinic Basel, Switzerland
| | | | | | | | | |
Collapse
|
37
|
Gherghel D, Orgül S, Gugleta K, Gekkieva M, Flammer J. Relationship between ocular perfusion pressure and retrobulbar blood flow in patients with glaucoma with progressive damage. Am J Ophthalmol 2000; 130:597-605. [PMID: 11078838 DOI: 10.1016/s0002-9394(00)00766-2] [Citation(s) in RCA: 144] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
PURPOSE To evaluate the relationship between ocular perfusion pressure and color Doppler measurements in patients with glaucoma. MATERIALS AND METHODS Twenty patients with primary open-angle glaucoma with visual field deterioration in spite of an intraocular pressure lowered below 21 mm Hg, 20 age-matched patients with glaucoma with stable visual fields, and 20 age-matched healthy controls were recruited. After a 20-minute rest in a supine position, intraocular pressure and color Doppler measurements parameters of the ophthalmic artery and the central retinal artery were obtained. Correlations between mean ocular perfusion pressure and color Doppler measurements parameters were determined. RESULTS Patients with glaucoma showed a higher intraocular pressure (P <.0008) and a lower mean ocular perfusion pressure (P <.0045) compared with healthy subjects. Patients with deteriorating glaucoma showed a lower mean blood pressure (P =.033) and a lower end diastolic velocity in the central retinal artery (P =.0093) compared with normals. Mean ocular perfusion pressure correlated positively with end diastolic velocity in the ophthalmic artery (R = 0.66, P =.002) and central retinal artery (R = 0.74, P <.0001) and negatively with resistivity index in the ophthalmic artery (R = -0.70, P =.001) and central retinal artery (R = -0.62, P =.003) in patients with deteriorating glaucoma. Such correlations did not occur in patients with glaucoma with stable visual fields or in normal subjects. The correlations were statistically significantly different between the study groups (parallelism of regression lines in an analysis of covariance model) for end diastolic velocity (P =.001) and resistivity index (P =.0001) in the ophthalmic artery, as well as for end diastolic velocity (P =.0009) and resistivity index (P =. 001) in the central retinal artery. CONCLUSIONS The present findings suggest that alterations in ocular blood flow regulation may contribute to the progression in glaucomatous damage.
Collapse
Affiliation(s)
- D Gherghel
- University Eye Clinic, Basel, Switzerland
| | | | | | | | | |
Collapse
|
38
|
Romerio SC, Linder L, Flammer J, Haefeli WE. Correlation between apolipoprotein B and endothelin-1-induced vasoconstriction in humans. Peptides 2000; 21:871-4. [PMID: 10959010 DOI: 10.1016/s0196-9781(00)00221-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Low-density lipoprotein (LDL) concentrations have been linked to altered responses to endogenous vasodilators and vasoconstrictors. We evaluated retrospectively the relationship between LDL and vasoconstrictor (endothelin-1, phenylephrine) responsiveness of the forearm vasculature in 15 elderly healthy volunteers with apolipoprotein B and LDL levels in the normal range. In contrast to phenylephrine, changes in forearm vascular resistance induced by endothelin-1 were correlated with apolipoprotein B, LDL, and total cholesterol concentrations in women but not in men. These findings might suggest that lipids may increase vascular tone through both impaired endothelial vasodilation and increased vasoconstriction to endothelin-1 at least in women.
Collapse
Affiliation(s)
- S C Romerio
- Division of Clinical Pharmacology, University Hospital, CH-4031, Basel, Switzerland
| | | | | | | |
Collapse
|
39
|
Abstract
There is clinical and experimental evidence that both increased intraocular pressure and disturbed circulation are involved in the pathogenesis of glaucomatous damage. Among the many factors discussed, decreased blood pressure and vasospasm are the most important, and these factors may, at least in part, be therapeutically influenced. The basic underlying disorder might be a vascular dysfunction leading to local vasospasm and to systemic hypotension.
Collapse
Affiliation(s)
- P Gasser
- Clinic of Medicine, Regionalspital, Lachen SZ, Switzerland
| |
Collapse
|
40
|
Abstract
Vascular disorders of the anterior optic nerve, historically, have been described as potential etiologic factors in the development of glaucomatous optic neuropathy. During the past several decades, clinical and experimental evidence of the involvement of vascular aberrations as a potential causative factor or associated risk factor have increased. However, the direct evidence that optic nerve ischemia contributes to glaucomatous optic neuropathy remains limited. Several questions about our current knowledge arise. Can ischemia alone or in combination with other factors cause glaucomatous optic neuropathy? Does our current knowledge of the vascular anatomy and physiology of the optic nerve allow us to understand vascular changes observed in individuals with glaucoma? Can we rely on current measurement techniques to assess and monitor the vascular beds of the optic nerve? This article summarizes the complex nature of the microcirculation in the anterior optic nerve, discusses the possible contribution of vascular factors in the development of glaucoma optic neuropathy, and examines the measurement techniques used in current studies.
Collapse
Affiliation(s)
- G A Cioffi
- Devers Eye Institute, Portland, OR 97210, USA
| | | |
Collapse
|
41
|
Orgül S, Gugleta K, Flammer J. Physiology of perfusion as it relates to the optic nerve head. Surv Ophthalmol 1999; 43 Suppl 1:S17-26. [PMID: 10416744 DOI: 10.1016/s0039-6257(99)00009-0] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Blood flow in the optic nerve has been demonstrated to be autoregulated, and, thus, within certain limits, to be independent of the local perfusion pressure. As in the brain, a close coupling of neuronal activity and optic nerve head blood flow has been demonstrated. A number of regulatory systems and factors participate in the regulation of vascular tone in various organs, including the optic nerve. Metabolic and myogenic mechanisms keep local perfusion constant or adapted to the local metabolic needs. Such mechanisms seem to be involved in the regulation of optic nerve blood flow as well. In contrast, neuronal blood flow regulation is of minor importance in the optic nerve. Many of the regulatory modalities induce a response of vascular smooth muscle cells through stimulation of factors produced by the endothelial cell layer. Indeed, endothelial factors are of utmost importance in the regulation of optic nerve blood flow. The facts that there is a basal formation of nitric oxide, which leads to an active dilation of the ocular vasculature, and that endothelin-1 decreases blood flow to the anterior optic nerve in a dose-dependent manner suggest that alterations in these regulatory mechanisms might be relevant for optic nerve blood flow alterations as they relate to glaucomatous optic neuropathy. It is hoped that a detailed knowledge of blood flow regulation in the optic nerve might initiate new treatment modalities in optic neuropathies that are hemodynamic and vascular in nature.
Collapse
Affiliation(s)
- S Orgül
- University Eye Clinic, Basel, Switzerland.
| | | | | |
Collapse
|