Autoregulation of Retinal Blood Flow in Response to Decreased Ocular Perfusion Pressure in Cats: Comparison of the Effects of Increased Intraocular Pressure and Systemic Hypotension

2014 ◽  
Vol 55 (1) ◽  
pp. 360 ◽  
Author(s):  
Tomofumi Tani ◽  
Taiji Nagaoka ◽  
Seigo Nakabayashi ◽  
Takafumi Yoshioka ◽  
Akitoshi Yoshida
Keyword(s):  
Blood Flow ◽  
Intraocular Pressure ◽  
Perfusion Pressure ◽  
Retinal Blood Flow ◽  
Ocular Perfusion Pressure ◽  
Systemic Hypotension ◽  
Ocular Perfusion

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.

Retinal Vascular Implications of Ocular Hypertension

2021 ◽  
Author(s):  
Fidan Jmor ◽  
John C. Chen
Keyword(s):  
Blood Flow ◽  
Diabetic Retinopathy ◽  
Intraocular Pressure ◽  
Vascular Anatomy ◽  
Flow Regulation ◽  
Retinal Blood Flow ◽  
Vein Occlusion ◽  
Ocular Perfusion ◽  
The Relationship ◽  
Central Retinal Vein

In this chapter, we review the basics of retinal vascular anatomy and discuss the physiologic process of retinal blood flow regulation. We then aim to explore the relationship between intraocular pressure and retinal circulation, taking into account factors that affect retinal hemodynamics. Specifically, we discuss the concepts of ocular perfusion pressure, baro-damage to the endothelium and transmural pressure in relation to the intraocular pressure. Finally, we demonstrate the inter-relationships of these factors and concepts in the pathogenesis of some retinal vascular conditions; more particularly, through examples of two common clinical pathologies of diabetic retinopathy and central retinal vein occlusion.

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