Role of Ocular Blood Flow in the Pathogenesis of Glaucoma

Glaucoma ◽  
2015 ◽  
pp. 88-97 ◽  
Author(s):  
Ali S Hafez ◽  
Mark R Lesk
Keyword(s):  
Blood Flow ◽  
Ocular Blood Flow

scholarly journals The Role of the Endothelin System in the Vascular Dysregulation Involved in Retinitis Pigmentosa

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Francesco Saverio Sorrentino ◽  
Claudio Bonifazzi ◽  
Paolo Perri
Keyword(s):  
Blood Flow ◽  
Retinitis Pigmentosa ◽  
Vascular System ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Ocular Blood Flow ◽  
The Body ◽  
Vascular Dysregulation ◽  
Endothelin System

Retinitis pigmentosa is a clinical and genetic group of inherited retinal disorders characterized by alterations of photoreceptors and retinal pigment epithelium leading to a progressive concentric visual field restriction, which may bring about severe central vision impairment. Haemodynamic studies in patients with retinitis pigmentosa have demonstrated ocular blood flow abnormalities both in retina-choroidal and in retroocular vascular system. Moreover, several investigations have studied the augmentation of endothelin-1 plasma levels systemically in the body and locally in the eye. This might account for vasoconstriction and ischemia, typical in vascular dysregulation syndrome, which can be considered an important factor of reduction of the ocular blood flow in subjects affected by retinitis pigmentosa.

scholarly journals THE ROLE OF OCULAR BLOOD FLOW IN THE PATHOGENESIS OF GLAUCOMA

2019 ◽  
Vol 19 (1) ◽  
pp. 51-54
Author(s):  
Yulia Primitasari ◽  
Evelyn Komaratih
Keyword(s):  
Blood Flow ◽  
Large Population ◽  
Visual Fields ◽  
Population Based ◽  
Ocular Blood Flow ◽  
Vascular Risk ◽  
Vascular Dysregulation ◽  
Primary Vascular Dysregulation ◽  
Flicker Stimulation

 Abstract. Glaucoma is currently the second leading cause of blindness worldwide and the prevalence is expected to increase. Despite lowering of IOP, vascular risk factors, genetics, and other systemic conditions could progress the glaucoma damage. Ocular blood flow has emerged as an increasingly prevalent glaucoma risk factor in large population-based trials. Abnormal  perfusion  and  the  subsequent  ischemia  of  the ONH  play  a  major  role  in  the  glaucomatous  damage. Ocular Blood flow is unstable if IOP fluctuates on a high enough or blood pressure on a low enough level to exceed temporarily the autoregulation capacity. IOP fluctuation is also related to both an increase in scotomas and an increase in diffuse visual fields damage.  OBF is unstable if autoregulation itself is disturbed. In  glaucoma  the  response  of  retinal  and  optic nerve head  blood flow to flicker  stimulation  is  reduced.  Primary  vascular  dysregulation appears  to  be  associated  with  abnormal  retinal  neurovascular  coupling,  because  vasospastic  subjects  show  a reduced  response  to  flicker  stimulation.Keywords: ocular blood flow, glaucoma

scholarly journals The Role of Ocular Blood Flow in the Pathogenesis of Glaucomatous Damage

2011 ◽  
Vol 04 (02) ◽  
pp. 84 ◽  
Author(s):  
Josef Flammer ◽  
Katarzyna Konieczka ◽  
Andreas J Flammer ◽  
◽  
◽  
...  
Keyword(s):  
Blood Flow ◽  
Oxygen Supply ◽  
Oxygen Depletion ◽  
Ocular Blood Flow ◽  
Primary Component ◽  
Blood Retinal Barrier ◽  
Related Factors ◽  
Primary Vascular Dysregulation ◽  
High Tension

Ocular blood flow (OBF) is on average lower in glaucoma patients than in healthy controls. This reduction is more pronounced in normal-tension than in high-tension glaucoma and more distinct in cases with progressing damage as compared to those with stable disease. Besides a secondary component caused by atrophy, there is an important primary component of OBF reduction, which also has a predictive value. The fact that hypoxia-related factors are upregulated in eyes of glaucoma patients indicates oxygen depletion. It is, however, not constant hypoxia, but rather the fluctuation of oxygen supply that leads to tissue damage, likely because of oxidative stress. Low perfusion pressure and disturbed autoregulation are the major causes of insufficient and fluctuating oxygen supply, and both systemic hypotension and disturbed autoregulation are often consequences of the primary vascular dysregulation syndrome. The observed splinter hemorrhages in these patients are a consequence of a local breakdown of the blood–brain or blood–retinal barrier. The often associated vein occlusions can be a consequence of a local vein dysregulation.

scholarly journals A review of ocular perfusion pressure and retinal thickness: A case for the role of systemic hypotension in glaucoma

2021 ◽  
Vol 80 (1) ◽  
Author(s):  
Naazia Vawda ◽  
Alvin J. Munsamy
Keyword(s):  
Blood Flow ◽  
Perfusion Pressure ◽  
Retinal Thickness ◽  
Ocular Blood Flow ◽  
Retinal Nerve Fibre Layer ◽  
Ocular Perfusion Pressure ◽  
Systemic Hypotension ◽  
Ocular Perfusion ◽  
Nerve Fibre Layer

Background: Ocular perfusion pressure (OPP) is defined as blood pressure (BP) minus intraocular pressure (IOP). Low OPP may result in decreased ocular blood flow (OBF) and oxygen to the optic nerve head (ONH) and retina.Aim: To review the role of systemic hypotension and similar conditions in OPP and its influence on retinal nerve fibre layer (RNFL) thickness and the ganglion cell complex (GCC).Method: A literature search was conducted using the following search terms: ‘systemic hypotension’; ‘glaucoma’; ‘retinal nerve fibre layer’; ‘optic nerve’; ‘ocular blood flow’ and ‘ocular perfusion pressure’.Results: The Los Angeles Eye Study and Barbados Eye Study found that decreased OPP and BP increased the risk of glaucoma development by up to six times. Reduced retinal perfusion with resultant thinning of the RNFL in conditions with a similar mechanism, such as obstructive sleep apnoea syndrome, has indicated the importance of reduced OPP in retinal thickness. In the absence of any study directly showing the effect of systemic hypotension on OPP and retinal thickness, a working hypothesis proposes that reduced BP with or without normal-to-raised IOP will reduce OPP. The reduced OPP and OBF in those with systemic hypotension may result in oxidative stress and hypoxia which may then cause retinal ganglion cell death and the resultant retinal thinning.Conclusion: The increased risk of glaucoma development and progression relating to decreased BP and OPP has been proven to be of importance. Monitoring patients with systemic hypotension and evaluating the macula, ONH RNFL and GCC thickness may alert clinicians to possible glaucomatous changes.

Lutein Complex Supplementation Increases Ocular Blood Flow Biomarkers in Healthy Subjects

2019 ◽  
Vol 89 (1-2) ◽  
pp. 5-12
Author(s):  
Alon Harris ◽  
Brent Siesky ◽  
Amelia Huang ◽  
Thai Do ◽  
Sunu Mathew ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Diastolic Blood Pressure ◽  
Healthy Subjects ◽  
Ocular Blood Flow ◽  
Capillary Blood ◽  
Post Treatment ◽  
Capillary Blood Flow ◽  
Doppler Imaging ◽  
Retinal Capillary

Abstract. Introduction: To investigate the effects of a lutein complex supplementation on ocular blood flow in healthy subjects. Materials and Methods: Sixteen healthy female patients (mean age 36.8 ± 12.1 years) were enrolled in this randomized, placebo-controlled, double-blinded, two-period crossover study. Subjects received daily an oral dose of the lutein with synergistic phytochemicals complex (lutein (10 mg), ascorbic acid (500 mg), tocopherols (364 mg), carnosic acid (2.5 mg), zeaxanthin (2 mg), copper (2 mg), with synergistic effects in reducing pro-inflammatory mediators and cytokines when administered together in combination) and placebo during administration periods. Measurements were taken before and after three-week supplementation periods, with crossover visits separated by a three-week washout period. Data analysis included blood pressure, heart rate, intraocular pressure, visual acuity, contrast sensitivity detection, ocular perfusion pressure, confocal scanning laser Doppler imaging of retinal capillary blood flow, and Doppler imaging of the retrobulbar blood vessels. Results: Lutein complex supplementation produced a statistically significant increase in mean superior retinal capillary blood flow, measured in arbitrary units (60, p = 0.0466) and a decrease in the percentage of avascular area in the superior (−0.029, p = 0.0491) and inferior (−0.023, p = 0.0477) retina, as well as reduced systolic (−4.06, p = 0.0295) and diastolic (−3.69, p = 0.0441) blood pressure measured in mmHg from baseline. Data comparison between the two supplement groups revealed a significant decrease in systemic diastolic blood pressure (change from pre- to post-treatment with lutein supplement (mean (SE)): −3.69 (1.68); change from pre- to post-treatment with placebo: 0.31 (2.57); p = 0.0357) and a significant increase in the peak systolic velocity (measured in cm/sec) in the central retinal artery (change from pre- to post-treatment with lutein supplement: 0.36 (0.19); change from pre- to post-treatment with placebo: −0.33 (0.21); p = 0.0384) with lutein complex supplement; data analyses from the placebo group were all non-significant. Discussion: In healthy participants, oral administration of a lutein phytochemicals complex for three weeks produced increased ocular blood flow biomarkers within retinal vascular beds and reduced diastolic blood pressure compared to placebo.

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