scholarly journals Ocular perfusion pressure and ocular blood flow in glaucoma

2013 ◽  
Vol 13 (1) ◽  
pp. 36-42 ◽  
Author(s):  
A Popa Cherecheanu ◽  
G Garhofer ◽  
D Schmidl ◽  
R Werkmeister ◽  
L Schmetterer
Keyword(s):  
Blood Flow ◽  
Perfusion Pressure ◽  
Ocular Blood Flow ◽  
Ocular Perfusion Pressure ◽  
Ocular Perfusion

scholarly journals Ocular Perfusion Pressure and Pulsatile Ocular Blood Flow in Normal and Systemic Hypertensive Patients

2015 ◽  
Vol 9 (1) ◽  
pp. 16-19 ◽  
Author(s):  
Syril Dorairaj ◽  
Fabio N Kanadani ◽  
Carlos R Figueiredo ◽  
Rafaela Morais Miranda ◽  
Patricia LT Cunha ◽  
...  
Keyword(s):  
Blood Flow ◽  
Perfusion Pressure ◽  
Ocular Blood Flow ◽  
Ocular Perfusion Pressure ◽  
Hypertensive Patients ◽  
Ocular Perfusion ◽  
Pulsatile Ocular Blood Flow

scholarly journals Ocular blood flow in steep Trendelenburg positioning during robotic-assisted radical prostatectomy

2017 ◽  
Vol 28 (3) ◽  
pp. 333-338 ◽  
Author(s):  
Christian L. Demasi ◽  
Francesco Porpiglia ◽  
Augusto Tempia ◽  
Savino D’Amelio
Keyword(s):  
Blood Flow ◽  
Radical Prostatectomy ◽  
Perfusion Pressure ◽  
Ocular Blood Flow ◽  
Ocular Perfusion Pressure ◽  
Trendelenburg Position ◽  
Robotic Assisted ◽  
Ocular Perfusion ◽  
Steep Trendelenburg Position ◽  
Pulsatile Ocular Blood Flow

Purpose: Several ischemic optic neuropathies that occurred during robotic-assisted laparoscopic radical prostatectomy (RALRP) have been reported to be due to the Trendelenburg position, which lowers ocular perfusion pressure (OPP). We examined changes in pulsatile ocular blood flow (POBF) and its correlation with OPP during RALRP in the steep Trendelenburg position. Methods: Pulsatile ocular blood flow and intraocular pressure (IOP) were measured in 50 patients by the OBF Langham System 5 times during RALRP. The mean arterial blood pressure (MAP), heart rate, plateau airway pressure, and end-tidal CO2 (EtCO2) at each time point were recorded. Ocular perfusion pressure was calculated from simultaneous IOP and MAP measurements. Results: Pulsatile ocular blood flow was 15.53 ± 3.32 µL/s at T0, 18.99 ± 4.95 µL/s at T1, 10.04 ± 3.24 µL/s at T2, 11.45 ± 3.02 µL/s at T3, and 15.07 ± 3.81 µL/s at T4. Ocular perfusion pressure was 70.15 ± 5.98 mm Hg at T0, 64.21 ± 6.77 mm Hg at T1, 57.71 ± 7.07 mm Hg at T2, 51.73 ± 11.58 mm Hg at T3, and 64.21 ± 12.37 mm Hg at T4. Repeated-measures analysis of variance on POBF and OPP was significant (p>0.05). This difference disappeared when the correlation between MAP and POBF, EtCO2 and POBF, and EtCO2 and OPP were considered, while correlation between MAP and OPP confirmed the difference. The regression analysis between POBF and OPP showed a statistically significant difference at T0 and T3 (r = 0.047, p = 0.031 and r = 0.096, p = 0.002, respectively). Conclusions: Pulsatile ocular blood flow and OPP reached the lowest level at the end of surgery.

scholarly journals Ocular Blood Flow Autoregulation Mechanisms and Methods

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Xue Luo ◽  
Yu-meng Shen ◽  
Meng-nan Jiang ◽  
Xiang-feng Lou ◽  
Yin Shen
Keyword(s):  
Blood Flow ◽  
Perfusion Pressure ◽  
Ocular Blood Flow ◽  
Flow Regulation ◽  
Main Function ◽  
Ocular Diseases ◽  
Ocular Perfusion Pressure ◽  
Metabolic Demand ◽  
Ocular Perfusion ◽  
Sufficient Oxygen

The main function of ocular blood flow is to supply sufficient oxygen and nutrients to the eye. Local blood vessels resistance regulates overall blood distribution to the eye and can vary rapidly over time depending on ocular need. Under normal conditions, the relation between blood flow and perfusion pressure in the eye is autoregulated. Basically, autoregulation is a capacity to maintain a relatively constant level of blood flow in the presence of changes in ocular perfusion pressure and varied metabolic demand. In addition, ocular blood flow dysregulation has been demonstrated as an independent risk factor to many ocular diseases. For instance, ocular perfusion pressure plays key role in the progression of retinopathy such as glaucoma and diabetic retinopathy. In this review, different direct and indirect techniques to measure ocular blood flow and the effect of myogenic and neurogenic mechanisms on ocular blood flow are discussed. Moreover, ocular blood flow regulation in ocular disease will be described.

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.

scholarly journals Evaluation of the circadian fluctuations of intraocular pressure and ocular perfusion pressure in different types of glaucoma

2018 ◽  
pp. 15-18
Keyword(s):  
Intraocular Pressure ◽  
Perfusion Pressure ◽  
Ocular Blood Flow ◽  
University Hospital ◽  
Ocular Perfusion Pressure ◽  
Goldmann Tonometry ◽  
Ocular Perfusion ◽  
Objective Evidence ◽  
Different Types ◽  
Exfoliative Glaucoma

Background: Glaucoma is a frequent leading cause of blindness. Objective evidence showed that it can be secondary to optic nerve head hypoperfusion and autonomic dysfunction, not only to ocular hypertension. This makes the assessment of ocular blood flow a crucial step in the management of this disease. Aim: To investigate the circadian fluctuations of the intraocular pressure (IOP) and of the mean ocular perfusion pressure (mOPP) in patients with different types of glaucoma. Materials and methods: Sixty-five eyes of 65 glaucoma patients, managed in the Ophthalmology Department of the Careggi University Hospital, Firenze, Italy (2012-2014). Among these eyes, 22 had normotensive glaucoma (NTG), 21 hypertensive glaucoma (HTG), and 22 exfoliative glaucoma (XTG). The IOP was measured by Goldmann tonometry and the blood pressure, both systolic (sBP) and diastolic (dBP), by Riva-Rocci sphygmomanometry, at three time points (8am, 2pm, 8pm). The mOPP was then calculated according to the formula mOPP = [2/3 (2/3 dBP + 1/3sBP) - IOP]. Results: The fluctuations of IOP and mOPP were statistically significant in all the studied eyes (p<0.001 for all the comparisons). Both IOP and mOPP showed significantly larger fluctuations in the XFG eyes than in the NTG and HTG ones (p<0.001 for IOP and p=0.001 for mOPP). Conclusions: In our study, the mOPP had larger circadian fluctuations in eyes with XFG than in those with NTG and HTG. This parameter deserves to be assessed in all types of glaucoma. Key words: Glaucoma, intraocular pressure, mean ocular perfusion pressure.

Effects of Blood Flow Restriction at Different Intensities on IOP and Ocular Perfusion Pressure

2020 ◽  
Vol 97 (4) ◽  
pp. 293-299
Author(s):  
Jesús Vera ◽  
Raimundo Jiménez ◽  
Beatríz Redondo ◽  
Amador García-Ramos
Keyword(s):  
Blood Flow ◽  
Perfusion Pressure ◽  
Blood Flow Restriction ◽  
Ocular Perfusion Pressure ◽  
Flow Restriction ◽  
Ocular Perfusion
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