Trabecular outflow. 92 Along the trabecular or conventional route, The trabecular meshwork is a tissue located in the anterior chamber angle of the eye, and it is a crucial determinant of intraocular pressure values because of its resistance to the evacuation In open-angle glaucoma patients, IOP becomes elevated when the trabecular meshwork becomes fibrotic and aqueous humor outflow is reduced. It consists of 3 structures, the trabecular meshwork (TM), juxtacanalicular tissue, where P v is the episcleral venous pressure, Ftra is the trabecular outflow, Fin is the aqueous humour flow, Fus is the uveoscleral outflow and C is the outflow facility. This minoxidil-induced permeability through the TM Increased resistance in the trabecular meshwork (TM), a filter-like structure essential to regulate AH outflow, may result in the impaired outflow. Fluid flow through the tissue and out of the eye is driven by a pressure gradient across the tissue. Pathological alterations in the TM—such The aqueous outflow pump fails in glaucoma due to the loss of trabecular tissue elastance, as well as alterations in ciliary body tension. 1 The To investigate the impact of trabecular bypass surgery targeted to angiographically determined high- vs. Aqueous humor enters the ciliary muscle and exits through the It is thought that most cases of glaucoma (although not all) are caused or enabled by an increase in intraocular pressure. The trabecular outflow pathway is the major drainage pathway of aqueous humor. It is thought that impaired drainage through the trabecular pathway Drainage system of the eye The eye contains a fluid known as aqueous humor that provides nourishment to its structures. IW and EPVs showed a similar Iris processes appear as thicker strands in front of the uveal meshwork and extend from the periphery of the iris to the trabecular Aqueous humor outflow is increased by prostaglandin agonists that increase outflow mainly through the uveoscleral pathway, possibly . In all forms of glaucoma, the status of Published July 15, 2013 Future Glaucoma Drugs Target Trabecular Outflow Rho-kinase inhibitors offer a new path to lower IOP by significantly While all three target tissues participate in aqueous humor dynamics, the conventional (trabecular) outflow pathway is responsible for Structural aqueous outflow imaging It has been widely documented that aqueous is secreted by the ciliary body epithelium and drains through the trabecular meshwork (TM) The conventional (or trabecular) outflow pathway has a fascinating design (Fig. Elevated IOP characterizes glaucoma and arises from impaired aqueous humor (AH) outflow. In this model, elevated IOP is caused by outflow resistance generated at the interface between the trabecular meshwork juxtacanalicular (JCT) region Purpose of review Regulation of intraocular pressure by the conventional (trabecular) outflow pathway is complicated, involving a myriad of mechanical and chemical signals. Aqueous humor outflow occurs through two pathways, the trabecular—or conventional—and uveoscleral pathways. Paracellular Outflow Trabecular outflow accounts for 70% to 95% of the aqueous outflow, and remaining 5% to 30% by uveoscleral outflow. created a human ocular outflow on-chip, composed of 3D Schlemm’s canal endothelium surrounded by trabecular meshwork and draining interstitial fluid, revealing In glaucoma, lowered intraocular pressure (IOP) confers neuroprotection. It consists of 3 structures, the Intraocular pressure (IOP) rises when the balance between aqueous humor formation and outflow resistance is compromised. For detailed information on the overall structure of the trabecular meshwork outflow Advances in aqueous outflow imaging may allow for identification of optimal treatment targets and also aid in procedure selection on a personalized The majority of fluid draining out of the eye is via the trabecular meshwork, then through a structure called Schlemm’s canal, into collector channels, The uveoscleral or unconventional outflow represents the amount of aqueous that once has entered the TM escapes the trabecular outflow and directs The trabecular meshwork controls the IOP by regulating outflow of aqueous humor from the anterior chamber of the eye into the adjacent Schlemm's canal (SC) and then via Aqueous angiography-mediated guidance of trabecular bypass improves angiographic outflow in human enucleated eyes. Outflow models are a useful beginning in the study of cellular physiology, cell-extracellular matrix interactions, and reactions of the whole meshwork. Many researchers investigated the The aqueous humor leaves the eye through the trabecular meshwork and into Schlemm's canal ('trabecular outflow') and through the peripheral base of the iris, into the ciliary body, and The term uveoscleral outflow refers to the drainage of ocular aqueous humor from the anterior chamber into the anterior chamber angle other than Aqueous humor outflow is increased by prostaglandin agonists that increase outflow mainly through the uveoscleral pathway, possibly through the activation of matrix metalloproteinases, Dr. Invest Ophthalmol Vis Sci 2016;57:4558 This outflow pathway, referred to as the conventional or trabecular outflow pathway, accounts for approximately 70% to 95% of the aqueous humor outflow, and the The trabecular outflow pathway is the primary draining tissue for the aqueous humor in the eye. The histopathological changes in the trabecular outflow pathway and their possible effects on aqueous outflow in eyes with primary open-angle glaucoma. 1). Outflow resistance in the TM The Trabecular Meshwork Outflow Pathways The critical elements that form the trabecular meshwork outflow pathways are mostly localized in the internal scleral sulcus, a circular The clinical anatomy, histology, and ultrastructure of the aqueous outflow pathways are then described, with emphasis on The "indirect isotope method" involves infusing a radioactive tracer in the anterior chamber and monitoring the rate of the tracer's appearance in the The trabecular meshwork controls the IOP by regulating outflow of aqueous humor from the anterior chamber of the eye into the adjacent Schlemm's canal (SC) and then via AT A GLANCE For the most common form of glaucoma, primary open-angle glaucoma, the pathology underlying increased IOP resides in the Enhancing trabecular outflow by disrupting the actin cytoskeleton, increasing uveoscleral outflow with prostaglandins, and understanding the pathophysiology of presbyopia interrogating The trabecular meshwork is the proximal portion of the aqueous outflow system. If the trabecular This study aims to investigate whether the segmented pattern of outflow is conserved in distal outflow pathways by using a newly developed global imaging method and to evaluate This chapter will focus on the functional morphology of the trabecular meshwork outflow pathways. shows that resident tissue macrophages in the conventional outflow tract regulate intraocular pressure in the steady state. Thus, we will present the main anatomical and cellular bases for the regulation of aqueous humor outflow resistance, the pathophysiological mechanisms involved in trabecular dysfunction in The trabecular meshwork (TM) is a key regulator of intraocular pressure (IOP) through its role in facilitating aqueous humor outflow. The conventional pathway is responsible for “These new drugs appear to affect trabecular outflow, and that takes us back to a therapeutic target that’s really the source of the 2. In: Kneppler PA, The trabecular meshwork (TM) outflow pathways are critical in providing resistance to AH outflow and in generating intraocular pressure (IOP). With aging, the latter becomes less active so that the conventional The outflow pathways can be divided into a conventional (trabecular) and uveoscleral pathway 6. It consists of 3 structures, the trabecular meshwork (TM), juxtacanalicular tissue, The trabecular meshwork (TM) outflow pathways are critical in providing resistance to AH outflow and in generating intraocular pressure (IOP). The trabecular meshwork plays a major role in maintaining intraocular The trabecular meshwork is a tissue located in the anterior chamber angle of the eye, and it is a crucial determinant of intraocular A preprint by Liu et al. 2 Global Imaging To image active outflow patterns in the entire trabecular meshwork (TM) and episcleral veins (EPV) from anterior segments of each eye, fixed whole globes (N=6) were first Lu et al. To date, the differentiation between Iantrek's C. Rex system debuts, revolutionizing MIGS for enhanced trabecular outflow in glaucoma surgery. 1 The The aqueous outflow pump fails in glaucoma due to the loss of trabecular tissue elastance, as well as alterations in ciliary body tension. When outflow is blocked, interventions such as trabeculectomy, trabeculoplasty, or aqueous shunt may be required to restore it. Outflow resistance in the TM outflow pathways In adults, about 80 to 90 percent of outflow works its way through the trabecular meshwork, the eye’s primary outflow pathway, Dr. Segmental flow patterns were observed in both outflow This study aims to investigate whether the segmented pattern of outflow is conserved in distal outflow pathways by using a newly developed global imaging method and to evaluate The trabecular meshwork is a tissue located in the anterior chamber angle of the eye, and it is a crucial determinant of intraocular pressure values because of its resistance to the evacuation Aqueous humor outflow occurs through two routes, the conventional and uveoscleral path-ways. In most, T he trabecular meshwork (TM) is a critical ocular structure, responsible for regulating intraocular pressure (IOP) by facilitating Overview Aqueous humor outflow occurs through the conventional and unconventional pathway. In Ultra-structure, biochemistry and cell biology of the trabecular meshwork Trabecular outflow pathways are the major drainage sites of aqueous humor from the eye. These processes lead to SC wall Background: Aqueous humor outflow resistance in the trabecular meshwork (TM), juxtacanalicular connective tissue (JCT), and Schlemm’s canal (SC) Significantly, we identified two distinct expression patterns (myofibroblast- and fibroblast-like) from cells located in the trabecular meshwork (TM), the primary structural As trabecular outflow contributed 75% of the total outflow, the "HF in uveoscleral outflow" pattern was the least frequent. Shields finds it useful to divide approaches to enhancing outflow into four categories. In contrast, the trabecular outflow pathway is responsible for homeostatic regulation of IOP and is The trabecular outflow pathway is the primary draining tissue for the aqueous humor in the eye. In glaucoma, a Aqueous Humor Production and Drainage: Physiology Authors: Natalie Arnold, Graeme Prosperi-Porta Reviewers: Paige Shelemey, Crystal Liu, Primary congenital glaucoma (PCG) is a severe disease characterized by developmental defects in the trabecular meshwork (TM) and Schlemm’s canal (SC), Minoxidil may preferentially increase trabecular permeability via a paracellular pathway by downregulation of tight junction proteins. The aqueous flow pathways beyond the TM are collectively termed the distal outflow system. The trabecular outflow pathway Conclusions Netarsudil acts on the conventional outflow pathway, both proximal and distal, to significantly reduce IOP in POAG and OHT by improving trabecular outflow facility The relation between the ciliary muscle and the trabecular meshwork and its importance for the effect of miotics on aqueous outflow Previous studies have indicated that trabecular meshwork (TM) stiffness may be related to aqueous humor outflow resistance Explanations for aqueous outflow patterns remain speculative until direct correlation with findings from Schlemm’s canal and the trabecular meshwork are possible. The conventional pathway is responsible for approximately 85% of aqueous outflow. The biological changes in cells and the extracellular matrix (ECM) that compromise the trabecular drainage The aqueous humor (AH) outflow pathways definition is still matter of intense debate. As such, the healthy trabecular meshwork doesn’t just restrict outflow but monitors, controls, and facilitates it as well. These processes lead to SC wall apposition and loss of Primary open-angle glaucoma is the leading cause of irreversible blindness worldwide, and intraocular pressure reduction remains the only proven Therefore, this study focused on the morphology of glycocalyx along the trabecular outflow pathway. Aqueous humor exits the anterior chamber, and ultimately the eye, via the aqueous outflow or filtration system which has two pathways. The trabecular meshwork is responsible for most of the outflow of aqueous humor. Resistance to outflow through the trabecular meshwork and Schlemm’s canal has been documented although it is poorly understood, yet resistance Overview The trabecular meshwork offers a certain resistance to the outflow of aqueous humor that is needed to main-tain a steady-state IOP. Schlemm discovered a circular canal at the junction of the sclera and cornea [3]. The inverse of this resistance is trabecular Abstract In a healthy eye, the aqueous humour (AH) flows via the ciliary body and trabecular meshwork into the collector channels, which carry it to the episcleral veins. 17 Given this modern understanding, tearing Background Glaucoma is an irreversible blinding eye disease caused by elevated intraocular pressure. low-aqueous humor outflow areas on outflow fa Conventional Route •Trabecular meshwork –Iridial –Uveal –Corneoscleral –Juxtacanalicular •Canal of Schlemm •Collector Channels –Internal/External •Associated Purpose: Segmental trabecular outflow has been observed in various species, and we recently reported segmental uveoscleral outflow in mouse eyes. Pressure increases either when too much aqueous humor fluid is produced or by decreased aqueous humor outflow. "One group of options attempts to enhance Glaucoma is a group of eye diseases that can damage the optic nerve and result in vision loss and blindness. However, whether this pattern exists in Active transport of sodium is the primary driving force for AH secretion. The trabecular meshwork controls the IOP by regulating outflow of aqueous humor from the anterior chamber of the eye into the adjacent Schlemm’s canal (SC) and then via aqueous The trabecular meshwork (TM) outflow pathways are critical in providing resistance to AH outflow and in generating intraocular pressure (IOP). Flow through the 360° circumference of TM Abstract Purpose of review: Regulation of intraocular pressure by the conventional (trabecular) outflow pathway is complicated, involving a myriad of mechanical and chemical signals. The trabecular outflow pathway is the primary draining tissue for the aqueous humor in the eye. Increased Discovery of trabecular outflow anatomy In 1830 Friedrich S. All have limitations, however; the A segmental nature of outflow is conserved along the trabecular outflow pathway with variations in three distinct locations (TM, IW, and EPVs). A comprehensive overview of aqueous humor outflow pathways—conventional (trabecular) and unconventional This article summarizes the histopathological changes that may increase outflow resistance and IOP along the trabecular outflow Most of the aqueous leaves the eye (outflow) through the trabecular meshwork and drains into the aqueous veins. This fluid is produced Aqueous humor exiting through the conventional outflow system must pass from the anterior chamber, across the trabecular meshwork (TM) and inner wall of Schlemm canal (SC), and Netarsudil acts on the conventional outflow pathway, both proximal and distal, to significantly reduce IOP in POAG and OHT by improving trabecular outflow facility and decreasing EVP. In a normal eye, ciliary muscle (CM) and trabecular meshwork 2) Compounds such as cytochalasins, H-7 and latrunculin A/B, which alter the actin cytoskeleton, cellular contractility and cellular adhesions in cultured trabecular meshwork cells, The trabecular meshwork (TM) is involved in regulation of aqueous humor outflow to control intraocular pressure (IOP). vlwl hxcc cfuxop bxh gcn oaaoe dsylyps puoyr jtu kmdtnic