Ocular Circulation

Riva, Charles E.; Alm, Albert; Pournaras, Constantin J.

doi:10.1016/b978-0-323-05714-1.00010-8

Cited by 31 publications

(36 citation statements)

References 386 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Aqueous humour (AH) is formed by ciliary processes in the posterior chamber (PC), and circulates through the pupil into the anterior chamber (AC). Most (90%) AH outflow is through passageways of trabecular meshwork, Schlemm's canal, collector channels and aqueous veins . Approximately 10% of AH drains through the anterior ciliary body, passing through extracellular spaces and diffusing into the suprachoroidal space to enter vortical veins.…”

Section: Water Balance In the Eyementioning

confidence: 99%

“…The passive permeability of the BAB depends on ionic concentration gradients. The anterior BAB featuring the anterior iris surface permits free access of AH to the stroma and iris muscles . Less permeable is the posterior BAB which features tight junctions present on cells of non‐pigmented ciliary epithelium; these are permeable to small, non‐ionic molecules such as sucrose .…”

Section: Water Balance In the Eyementioning

confidence: 99%

“…Most (90%) AH outflow is through passageways of trabecular meshwork, Schlemm's canal, collector channels and aqueous veins. 25 Approximately 10% of AH drains through the anterior ciliary body, passing through extracellular spaces and diffusing into the suprachoroidal space to enter vortical veins. The sclera is approximately 10% less hydrated than the cornea, and its hydration is strongly influenced by extracellular proteoglycan concentration.…”

Section: Water Balance In the Eyementioning

confidence: 99%

See 2 more Smart Citations

Hydration, fluid regulation and the eye: in health and disease

Sherwin

Kokavec

Thornton

2015

Clinical Exper Ophthalmology

View full text Add to dashboard Cite

Variation in systemic hydration status, namely chronic systemic hypohydration or dehydration, can influence the development of several chronic non-ophthalmic diseases. Owing to the eye's high water content and unique system of fluid regulation, we hypothesized that hydration status may affect the eye in health and disease states. Therefore, we performed a systematic review of the current evidence implicating changes in hydration and their association with ocular physiology and morphological characteristics. We also reviewed relevant clinical correlations of changes in hydration and major common eye diseases. Our findings suggest that systemic hydration status broadly affects a variety of ocular pathophysiologic processes and disease states. For example, dehydration may be associated with development of dry eye syndrome, cataract, refractive changes and retinal vascular disease. On the other hand, excessive hydration is associated with some ocular diseases. Tear fluid osmolarity may be an effective marker of systemic hydration status. Recent studies implicate chronic renin-angiotensin-aldosterone system activation in the pathogenesis of diabetic retinopathy and glaucoma but also suggest its antagonism may be a useful therapeutic target. Our findings indicate that assessment of hydration status may be an important consideration in the management of patients with chronic eye diseases and undergoing eye surgery. Further research investigating the role of acute and chronic changes in hydration in individuals with and without ocular disease is warranted.

show abstract

Section: Water Balance In the Eyementioning

confidence: 99%

Section: Water Balance In the Eyementioning

confidence: 99%

Section: Water Balance In the Eyementioning

confidence: 99%

See 1 more Smart Citation

Hydration, fluid regulation and the eye: in health and disease

Sherwin

Kokavec

Thornton

2015

Clinical Exper Ophthalmology

View full text Add to dashboard Cite

show abstract

“…2C shows the extent of the RPC's surrounding the optic nerve head in the human. For detailed reviews of the retinal vasculature, see Chan-Ling (2008), Pournaras et al (2008), Riva et al (2011).…”

Section: Introductionmentioning

confidence: 99%

Cellular and physiological mechanisms underlying blood flow regulation in the retina and choroid in health and disease

Kur

Newman

Chan‐Ling

2012

Progress in Retinal and Eye Research

541

455

View full text Add to dashboard Cite

We review the cellular and physiological mechanisms responsible for the regulation of blood flow in the retina and choroid in health and disease. Due to the intrinsic light sensitivity of the retina and the direct visual accessibility of fundus blood vessels, the eye offers unique opportunities for the non-invasive investigation of mechanisms of blood flow regulation. The ability of the retinal vasculature to regulate its blood flow is contrasted with the far more restricted ability of the choroidal circulation to regulate its blood flow by virtue of the absence of glial cells, the markedly reduced pericyte ensheathment of the choroidal vasculature, and the lack of intermediate filaments in choroidal pericytes. We review the cellular and molecular components of the neurovascular unit in the retina and choroid, techniques for monitoring retinal and choroidal blood flow, responses of the retinal and choroidal circulation to light stimulation, the role of capillaries, astrocytes and pericytes in regulating blood flow, putative signaling mechanisms mediating neurovascular coupling in the retina, and changes that occur in the retinal and choroidal circulation during diabetic retinopathy, age-related macular degeneration, glaucoma, and Alzheimer's disease. We close by discussing issues that remain to be explored.

show abstract

“…Cells of the retina are perfused by the retinal and choroidal circulations . Both are derived from the ophthalmic artery, a branch of the internal carotid artery.…”

Section: Overview Of Retinal Blood Supplymentioning

confidence: 99%

Neuronal activity‐dependent regulation of retinal blood flow

Noonan

Lamoureux

Sarossy

2015

Clinical Exper Ophthalmology

View full text Add to dashboard Cite

Blood flow in the retina is intrinsically regulated to meet the metabolic demands of its constituent cells. Flickering light or stationary contrast reversals induce an increase in blood flow within seconds of the stimulus onset. This phenomenon is thought to compensate for an increase in ganglion cell activity and energy consumption. Ganglion cell activity is in turn dependent on signals from photoreceptors, bipolar cells, horizontal cells and amacrine cells. The physiological properties of these neurons determine how each type is affected by a particular light characteristic. Neuronal activity then triggers the release of signalling molecules that dilate local blood vessels and increase blood flow. Nitric oxide has been implicated as an important mediator, but metabolites of arachidonic acid may also be involved. Detailed elucidation of these mechanisms, together with advances in imaging technology, may facilitate the use of neurovascular tests to improve the detection of retinal damage in pathological conditions.

show abstract

Ocular Circulation

Cited by 31 publications

References 386 publications

Hydration, fluid regulation and the eye: in health and disease

Hydration, fluid regulation and the eye: in health and disease

Cellular and physiological mechanisms underlying blood flow regulation in the retina and choroid in health and disease

Neuronal activity‐dependent regulation of retinal blood flow

Contact Info

Product

Resources

About