The Dynamics of Aqueous Humor Outflow—A Major Review

Aqueous humor outflow occurs through the conventional and unconventional pathway. With aging, the latter becomes less active so that the conventional pathway remains the primary mechanism of aqueous humor outflow. An abnormality of this pathway contributes significantly to disordered aqueous humor dynamics and consequent rise in intraocular pressure seen in primary open angle glaucoma and ocular hypertension. Recently, the ocular lymphatics have been implicated in aqueous humor outflow. Additionally, the trabecular meshwork is now understood to be a complex organization of structures, which are controlled by various biomechanical and biochemical mechanisms. Among others, these include the actinomyosin cytoskeletal system, extracellular matrix, intracellular signaling responses mediated by protein kinase C, Rho/Rho kinase, and other biologic factors. This review shall describe the various pathophysiologic mechanisms involved in aqueous humor dynamics.

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A fluorophotometric study on the aqueous humor dynamics in primary open angle glaucoma

International Ophthalmology ◽

10.1007/bf00917982 ◽

1992 ◽

Vol 16 (4-5) ◽

pp. 311-314 ◽

Cited By ~ 5

Author(s):

P. Beneyto Martin ◽

P. C. Fern�ndez Vila ◽

T. M. P�rez Martinez ◽

D. Aliseda Per�z

Keyword(s):

Aqueous Humor ◽

Primary Open Angle Glaucoma ◽

Open Angle Glaucoma ◽

Open Angle ◽

Aqueous Humor Dynamics

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Progressive spectacle correction in patients with ametropia and primary open-angle glaucoma

The Eye ◽

10.33791/2222-4408-2019-1-6-12 ◽

2019 ◽

Vol 125 (2019-1) ◽

pp. 6-12

Author(s):

Irina Gndoyan ◽

Natalya Kuznetsova ◽

Alexander Derevyanchenko

Keyword(s):

Intraocular Pressure ◽

Aqueous Humor ◽

Primary Open Angle Glaucoma ◽

Open Angle Glaucoma ◽

Main Group ◽

Control Group ◽

Open Angle ◽

Aqueous Humor Outflow ◽

Vision Correction ◽

Spectacle Correction

Purpose: To determine the role that progressive spectacle lenses play in intraocular pressure compensation and stabilization of the glaucomatous process in patients with primary open-angle glaucoma (POAG) combined with presbyopia and refractive errors. Material and methods. 29 patients (53 eyes) aged 43 to 67 years with I-II stage POAG and a certain type of refractive error were enrolled into study. All patients had intraocular pressure (IOP) compensated to the target level on medication. Patients of the main group (17 people, 32 eyes) used universal progressive spectacle lenses with optimized surface. The patients of the control group (12 people, 21 eyes) used separate monofocal glasses for near and distance vision as a method of ametropia correction. Visual acuity test, refractometry, pneumotonometry, tonography, automated static perimetry were applied for monitoring the patients. The measurements were taken before spectacle correction and a year after its prescription. Results. A decrease of IOP (p=0.01) and an increase of the aqueous humor outflow coefficient (p<0.01) were determined after one year use of the recommended type of vision correction in the main group, whereas in the control group there was an increased level of IOP (p<0.05) and a reduced aqueous humor outflow coefficient (p<0.2). Conclusion. The use of progressive spectacle lenses as a method of permanent vision correction reliably reduces IOP and improves the aqueous humor outflow in patients with early-stage POAG. The absence of negative visual field dynamics indicates the stabilization of the glaucomatous process.

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Role of MCP-1 and IL-8 in viral anterior uveitis, and contractility and fibrogenic activity of trabecular meshwork cells

Scientific Reports ◽

10.1038/s41598-021-94391-2 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Jiyoung Lee ◽

Jin A. Choi ◽

Hyun-hee Ju ◽

Ju-Eun Kim ◽

Soon-Young Paik ◽

...

Keyword(s):

Viral Infection ◽

Aqueous Humor ◽

Trabecular Meshwork ◽

Anterior Uveitis ◽

Rho Gtpase ◽

Open Angle Glaucoma ◽

Focal Adhesions ◽

Aqueous Humor Outflow ◽

Trabecular Meshwork Cells ◽

Aqueous Outflow

AbstractThe inflammatory chemokines, monocyte chemoattractant protein (MCP)-1 and IL-8, are produced by normal trabecular meshwork cells (TM) and elevated in the aqueous humor of primary open angle glaucoma (POAG) and hypertensive anterior uveitis associated with viral infection. However, their role in TM cells and aqueous humor outflow remains unclear. Here, we explored the possible involvement of MCP-1 and IL-8 in the physiology of TM cells in the context of aqueous outflow, and the viral anterior uveitis. We found that the stimulation of human TM cells with MCP-1 and IL-8 induced significant increase in the formation of actin stress fibers and focal adhesions, myosin light chain phosphorylation, and the contraction of TM cells. MCP-1 and IL-8 also demonstrated elevation of extracellular matrix proteins, and the migration of TM cells. When TM cells were infected with HSV-1 and CMV virus, there was a significant increase in cytoskeletal contraction and Rho-GTPase activation. Viral infection of TM cells revealed significantly increased expression of MCP-1 and IL-8. Taken together, these results indicate that MCP-1 and IL-8 induce TM cell contractibility, fibrogenic activity, and plasticity, which are presumed to increase resistance to aqueous outflow in viral anterior uveitis and POAG.

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Cellular crosstalk regulates the aqueous humor outflow pathway and provides new targets for glaucoma therapies

Nature Communications ◽

10.1038/s41467-021-26346-0 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Benjamin R. Thomson ◽

Pan Liu ◽

Tuncer Onay ◽

Jing Du ◽

Stuart W. Tompson ◽

...

Keyword(s):

Aqueous Humor ◽

Open Angle Glaucoma ◽

Severe Disease ◽

Congenital Glaucoma ◽

Loss Of Function ◽

Developmental Defects ◽

Aqueous Humor Outflow ◽

Risk Alleles ◽

Adult Mice ◽

Outflow Pathway

AbstractPrimary congenital glaucoma (PCG) is a severe disease characterized by developmental defects in the trabecular meshwork (TM) and Schlemm’s canal (SC), comprising the conventional aqueous humor outflow pathway of the eye. Recently, heterozygous loss of function variants in TEK and ANGPT1 or compound variants in TEK/SVEP1 were identified in children with PCG. Moreover, common variants in ANGPT1and SVEP1 have been identified as risk alleles for primary open angle glaucoma (POAG) in GWAS studies. Here, we show tissue-specific deletion of Angpt1 or Svep1 from the TM causes PCG in mice with severe defects in the adjacent SC. Single-cell transcriptomic analysis of normal and glaucomatous Angpt1 deficient eyes allowed us to identify distinct TM and SC cell populations and discover additional TM-SC signaling pathways. Furthermore, confirming the importance of angiopoietin signaling in SC, delivery of a recombinant ANGPT1-mimetic promotes developmental SC expansion in healthy and Angpt1 deficient eyes, blunts intraocular pressure (IOP) elevation and RGC loss in a mouse model of PCG and lowers IOP in healthy adult mice. Our data highlight the central role of ANGPT1-TEK signaling and TM-SC crosstalk in IOP homeostasis and provide new candidates for SC-targeted glaucoma therapy.

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Matrix Metalloproteinase and Their Inhibitors Concentration and Activity Variations in Aqueous Humor and Plasma of Glaucoma Patients

Revista de Chimie ◽

10.37358/rc.17.8.5775 ◽

2017 ◽

Vol 68 (8) ◽

pp. 1829-1833

Author(s):

Iulia Maria Ciotu ◽

Alina Constantin ◽

Liliana Voinea ◽

Valeriu Atanasiu

Keyword(s):

Extracellular Matrix ◽

Matrix Metalloproteinase ◽

Aqueous Humor ◽

Open Angle Glaucoma ◽

The Body ◽

Plasma Samples ◽

Open Angle ◽

Aqueous Humor Outflow ◽

Cataract Patients

Matrix metalloproteinases (MMPs) are a group of endopeptidases with the role of reorganizing the extracellular matrix of cells through the body. In aqueous humor MMPs have an important role in turnover regulation by acting on the constant remodeling of the trabecular mesh keeping at a constant level the trabecular resistance for a good aqueous humor outflow and consequently of the intraocular pressure.In this paper, we aimed to assess the levels of MMP-2/TIMP-1 and MMP-9/TIMP-2 ratio in aqueous humor samples and in the plasma of patients with open angle glaucoma and cataract patients that serves as control, and to evaluate the gelatinolytic activity MMP-2 and MMP-9 in aqueous humor samples. Aqueous humor and plasma samples were collected from 30 patients, 14 from open angle glaucoma and 16 from cataract patients. Levels of MMP-2, -9 and TIMP -1 and -2 were determined by zymography and immunoassays, using specific kits. The data obtained suggest the presence of a direct correlation between the levels and activity of MMP influencing the accumulation of abnormal matrix and may have an impact on the pathogenesis of open angle glaucoma.\

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Faculty Opinions recommendation of The effect of selective laser trabeculoplasty on aqueous humor dynamics in patients with ocular hypertension and primary open-angle glaucoma.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.717953566.793459172 ◽

2012 ◽

Author(s):

Carol Toris

Keyword(s):

Ocular Hypertension ◽

Aqueous Humor ◽

Primary Open Angle Glaucoma ◽

Open Angle Glaucoma ◽

Open Angle ◽

Selective Laser Trabeculoplasty ◽

Laser Trabeculoplasty ◽

Aqueous Humor Dynamics

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The Effect of Selective Laser Trabeculoplasty on Aqueous Humor Dynamics in Patients With Ocular Hypertension and Primary Open-angle Glaucoma

Journal of Glaucoma ◽

10.1097/ijg.0b013e31825af0eb ◽

2013 ◽

Vol 22 (9) ◽

pp. 746-749 ◽

Cited By ~ 8

Author(s):

Laura Beltran-Agullo ◽

Pouya Alaghband ◽

Adanna Obi ◽

Rahat Husain ◽

Kin-Sheng Lim

Keyword(s):

Ocular Hypertension ◽

Aqueous Humor ◽

Primary Open Angle Glaucoma ◽

Open Angle Glaucoma ◽

Open Angle ◽

Selective Laser Trabeculoplasty ◽

Laser Trabeculoplasty ◽

Aqueous Humor Dynamics

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Pharmacologic Trabeculectomy—Modulation of Aqueous Humor Outflow Through the Trabecular Meshwork

US Ophthalmic Review ◽

10.17925/usor.2015.8.1.46 ◽

2015 ◽

Vol 8 (1) ◽

pp. 46

Author(s):

Syed Shoeb Ahmad ◽

Syed Zia-ur-Rahman ◽

Norlina Ramli ◽

Shuaibah Abdul Ghani ◽

◽

...

Keyword(s):

Aqueous Humor ◽

Trabecular Meshwork ◽

Ciliary Body ◽

Aqueous Humor Outflow ◽

Aqueous Humor Dynamics ◽

Aqueous Outflow

“Pharmacologic trabeculectomy” is a term used to describe the modulation of aqueous outflow by the biochemical manipulation of the trabecular meshwork. Most of the medications currently in use either reduce aqueous production or increase its outflow through the ciliary body. However, there is a new group of agents being investigated, which can increase the facility of aqueous humor outflow through the trabecular meshwork. Thus, these agents will be able to provide a more physiologic means to control aqueous humor dynamics. This review sheds light on this concept of “medical trabeculectomy.”

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