Uveoscleral outflow diagram. Schematic diagram of the aqueous humor cycle.

Uveoscleral outflow diagram. 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 into the canal itself. The balance between the two routes is established by the ciliary mus-cle tone. The outflow rate through this route tends to decrease with age so that the conventional pathway has to take up more function of aqueous outflow. There is a single source of inflow: the secretion of aqueous Sep 22, 2014 · There is a simultaneous decrease in uveoscleral outflow, thus the AH outflow gets distributed between the conventional and unconventional pathways, depending on the tone of the ciliary muscle. 1 For the most common form of glaucoma, primary Download scientific diagram | Aqueous humor production and outflow in the eye. Elevated intraocular pressure occurs as the result of impaired aqueous humor outflow. The "indirect isotope method" involves infusing a radioactive tracer in the anterior chamber and monitoring the rate of the tracer's appearance in the blood (trabecular outflow) and the rate of the tracer's disappearance from the anterior chamber (aqueous flow). To date, the differentiation between conventional (trabecular meshwork) and unconventional (uveoscleral) pathways is widely accepted, distinguishing the different impact of the intraocular pressure on the AH outflow rate. Outflow drugs may affect one or the other outflow pathways to lower IOP. Aqueous humor outflow refers to the process by which aqueous humor is drained from the eyeball through a series of pathways, primarily the conventional trabecular meshwork-Schlemm's Canal pathway and additional unconventional pathways such as the uveoscleral and lymphatic pathways, maintaining intraocular pressure and fluid homeostasis. The majority of glaucoma medications control IOP by three main mechanisms: (1) increasing aqueous humor (AH) outflow via the trabecular meshwork (TM) pathway, (2) increasing AH outflow via the uveoscleral outflow pathway, or (3) decreasing the production of AH. In non-human primates 40–50% of aqueous leaves the eye by the uveoscleral route. However, the existence of the segmental flow pattern in uveoscleral outflow and its correlation with trabecular outflow in other species remain unknown. Enhancing trabecular outflow by disrupting the actin cytoskeleton, increasing uveoscleral outflow with prostaglandins, and understanding the pathophysiology of presbyopia interrogating Mother Nature: asking why, asking how, recognizing the signs, following the trail. The green arrows indicate a conventional pathway. Since imaging of uveoscleral outflow is more challenging, this review will focus on imaging of conventional (trabecular) outflow heretofore designated as trabecular, conventional, or simply aqueous humor outflow (AHO). An emerging therapeutic strategy Back to TopBack to Top Dec 1, 2023 · However, prostaglandin analogs have the theoretical benefit of bypassing the dysfunctional trabecular meshwork by increasing uveoscleral outflow and can be used after the acute phase is over. . The conventional pathway is responsible for approximately 85% of aqueous outflow. Keywords: Aqueous humor, glaucoma, intra-ocular pressure (IOP). Download scientific diagram | Aqueous humor outflow pathway. (a) Diagram of the anterior segment of the human eye, which includes the cornea, iris, ciliary body (CB), and lens. Historically, scleral allograft tissue has been clinically utilized during ocular surgery. Sep 3, 2010 · Fig. 2,5 The uveovortex pathway Oct 1, 2003 · Open in Viewer FIGURE 1. (A) Aqueous humor (AH, green arrows) exits the anterior chamber through the uveoscleral meshwork (UM Jan 10, 2025 · The ciliary muscle influences uveoscleral outflow, the reduction of which is thought to be due to ciliary muscle ECM degradation by pseudoexfoliative deposits [78, 109]. They have a limited duration of viability. Uveoscleral outflow is the difference between aqueous flow and trabecular outflow. Aqueous humor provides nourishment in the form of oxygen and micro-/macro-molecules such as glucose to avascular tissues like the crystalline lens and cornea. The uveoscleral outflow pathway refers to drainage of aqueous humour from the anterior chamber to the anterior angle other than through the trabecular meshwork. Sep 23, 2024 · Uveoscleral outflow is thought to be driven or changed by pressure gradients through the uvea, by movements of the ciliary muscle, and by cytoskeletal alterations or changes in the extracellular matrix within the drainage tissues. (B) A magnified view of trabecular meshwork (TM) depicting distal regions including collector channel entrances (CCE), collector channels (CC), episcleral vein (EV), and aqueous vein (AV). The inset shows the outflow pathways. This pathway operates with little resistance due to the absence of structured walls in the clefts it comprises, resulting in a low-pressure gradient for This uveoscleral outflow of aqueous humour accounts for 40-60% of the total outflow in monkeys, whereas it is considerably less in (3-8%) in cats and rabbits. Unlike the pathway for aqueous outflow through the trabecular meshwork, discussed later, flow through the uveoscleral pathway is thought generally to be pressure independent. (A) Diagram of the anterior segment of the human eye, which includes the cornea, iris, ciliary body (CB), and lens. Aqueous humor is produced by the ciliary body, in uveoscleral route, it flows from the posterior chamber through the pupil into the anterior chamber and then (shown by dashed lines and arrowheads) through the face of the ciliary body and iris root to the ciliary muscle and suprachoroidal space to either veins in the choroid and The uveoscleral outflow pathway is relatively independent of the intraocular pressure and the proportion of aqueous humor exiting the eye via the uveoscleral pathway decreases with age. Sep 15, 2016 · The uveoscleral pathway is regarded as a minor route for aqueous outflow and shall be discussed here first. AH is secreted by the CB and circulates (blue arrows Download scientific diagram | Schematic of the conventional outflow pathway. Jun 11, 2024 · Published 11 June 2024 Aqueous Outflow Mechanisms An introduction to the pulsatile flow motion model and its implications for developing future procedures. (A) Schematic diagram depicting conventional and uveoscleral pathway in the anterior eye chamber. Outflow models are a useful beginning in the study of cellular physiology, cell-extracellular matrix interactions, and reactions of the whole meshwork. It is secreted to the posterior chamber and reaches the anterior chamber by crossing the pupil. The aqueous humor is formed in the ciliary processes from arterial blood. Additionally, while uveoscleral outflow has a significant IOP-lowering effect, randomized comparisons with trabecular outflow surgery or incremental to trabecular intervention also are needed. Primary open-angle glaucoma is the leading cause of irreversible blindness worldwide, and intraocular pressure reduction remains the only proven treatment strategy. Aqueous humor is produced by the ciliary body and moves through the pupil into the anterior chamber where it A: Image of the anterior chamber of the eye. Studies however show that aqueous outflow through the unconventional route can vary from 4-60%. 1. As unconventional outflow is pressure-insensitive under normal conditions, and because at least a fraction of this outflow passes through the uveovortex pathway, we would suggest that the terms “uveoscleral” and “pressure-independent flow” are misleading and can lead to incorrect conclusions about the nature of this route, particularly Within the green box is the pathway for uveoscleral outflow showing how aqueous humor moves in many directions through multiple tissues before exiting the eye. 5 Uveoscleral Outflow The second route for AH out o w within the eye is through the unconventional out- We would like to show you a description here but the site won’t allow us. odels used in the laboratory to study aqueous outflow. The unconventional pathway involves drainage into the orbital vasculature, vortex veins and ciliary lymphatics, contributing up to 25-40% of total aqueous outflow in cynomolgus and vervet monkey models. Microinvasive canal surgery is dependent on the integrity of the trabecular meshwork, collector channels and downstream venous network for favorable outcomes. Aqueous humor exits the anterior chamber via two routes: the uveoscleral or nonconventional outflow pathway and the trabecular or conventional pathway, which comprises the trabecular meshwork (TM) and Schlemm’s canal. 1-cornea; 2-sclera; 3-anterior chamber; 4-pupil; 5-iris; 6-ciliary body; 7-lens; 8-suspensory ligament; 9 Mar 14, 2025 · It drains out of the eye through the trabecular meshwork (TM) and uveoscleral outflow route. The TM pathway is believed to be responsible for approximately 85% of aqueous outflow. Aqueous humor and its intraocular flow (aqueous humor outflow [AHO]) supports this by performing several functions. , flow rate), how much does it contribute to total outflow, and can we use the uveoscleral pathway better? Sep 12, 2024 · New research published in the peer-reviewed Journal of Clinical Medicine details the use of Iantrek Inc’s uveoscleral outflow technology (CycloPen Micro-Interventional System) as an advanced surgical technique for patients diagnosed with open-angle glaucoma (OAG). Oct 1, 2003 · Open in Viewer FIGURE 1. For the purpose of this review, we concentrated on the imaging of conventional aqueous outflow. Shields explains that the uveoscleral outflow route can be thought of as consisting of two segments—the uveal portion and the scleral portion—through which aqueous makes its way during its journey out of the eye. AHO creates The primary anatomic structures vital to the homeostasis of aqueous humor include the ciliary body as the site of principle production, and the trabecular meshwork and uveoscleral pathway as the sites of primary outflow 26, 31. It then drains primarily via the trabecular meshwork and Schlemm’s canal (the conventional outflow pathway) or, to a lesser extent, via the uveoscleral pathway (the unconventional outflow). B: The aqueous humor outflow consists of two pathways: the conventional outflow and the uveoscleral outflow. Aqueous humor is produced by the ciliary body, in uveoscleral route, it flows from the posterior chamber through the pupil into the anterior chamber and then (shown by dashed lines and arrowheads) through the face of the ciliary body and iris root to the ciliary muscle and suprachoroidal space to either veins in the Fig. The term uveoscleral outflow refers to the drainage of ocular aqueous humor from the anterior chamber into the anterior chamber angle other than through the trabecular meshwork (Figure). from publication: Rho Kinase (ROCK The uveoscleral pathway is defined as an anatomical route for aqueous humor outflow, which flows from the anterior chamber through interstitial spaces in the ciliary body and sclera, eventually draining into the intrascleral venous plexus. from publication: Current methods and new approaches to assess aqueous humor dynamics | Introduction: Aqueous humor and its Mar 19, 2010 · The Uveoscleral Pathway Dr. Schematic diagram of outflow pathway and structures in the Trabecular Meshwork. The conference discussion topics focused on what precisely is the uveoscleral outflow pathway, how are relevant physiological parameters within uveoscleral outflow measured (e. The primary anatomic structures vital to the homeostasis of aqueous humor include the ciliary body as the site of principle production, and the trabecular meshwork and uveoscleral pathway as the sites of primary outflow 26, 31. Although the conventional route is recognized to host the main sites for intraocular The molecular pathways that modulate uveoscleral and trabecular outflow are complex. Aqueous humor exits the anterior chamber via two routes: the uveoscleral or nonconventional outflow pathway and the Conclusion Augmenting the uveoscleral outflow pathway with implantation of suprachoroidal devices represents an alternative approach for treating glaucoma without creating a filtering bleb. • The mouse is a promising model for studying aqueous humor Mar 14, 2025 · It drains out of the eye through the trabecular meshwork (TM) and uveoscleral outflow route. Jun 1, 2025 · Because the uveoscleral pathway accounts for 5% to 30% of aqueous humor outflow, the supraciliary space has been targeted for innovative drainage strategies, including microinvasive glaucoma surgeries (MIGS). Source publication +3 A comprehensive overview of aqueous humor outflow pathways—conventional (trabecular) and unconventional (uveoscleral)—and their role in intraocular pressure regulation, with clinical correlations and surgical insights. Pathophysiology of Glaucoma We would like to show you a description here but the site won’t allow us. Schematic diagram illustrating the trabecular meshwork conventional outflow pathway. Pilocarpine should be avoided as it has been reported to exacerbate angle recession. (2). Microscopic agnostic features. (B) A magnified Download scientific diagram | Uveoscleral outflow by an invasive method. Mar 1, 2017 · Schematic diagram of outflow pathway and structures in the Trabecular Meshwork. Back to TopBack to Top Dec 1, 2023 · However, prostaglandin analogs have the theoretical benefit of bypassing the dysfunctional trabecular meshwork by increasing uveoscleral outflow and can be used after the acute phase is over. Cell cultures are less expensive, easier to obtain Download scientific diagram | The trabecular meshwork/Schlemm's canal (TM/SC) outflow pathway. 1: Cton = Ctrab + Cfu + Cps. This facility is about 10-fold less than trabecu-lar outflow facility. Both a passive model and a dynamic model have been used to explain trabecular outflow resistance. 1 The primary constituent is the trabecular meshwork (TM), which consists of seven to eight layers of cellular beams surrounded by extracellular matrix (ECM) in human eyes. Cfu is the facility of fluid flow through the ciliary muscle. The trabecular meshwork consists of three layers - uveal meshwork, corneoscleral meshwork, and The conventional outflow provides a majority of the aqueous drainage through the trabecular meshwork. Download scientific diagram | e Diagram of conventional ( black arrow ) and uveoscleral ( green arrow ) outflow within the anterior chamber of the eye. Uveoscleral (unconventional) outflow represents a small proportion of total aqueous drainage [7] and cannot be accurately imaged [8]. Schematic diagram illustrating the uveoscleral outflow pathway. 24,25 This pathway conveys aqueous humor from the anterior chamber into the portion of the ciliary muscle that is directly accessible from the anterior chamber angle. Though not yet proven, the effect of the nitric oxide may be analogous to that of ROCK inhibitors—altering contractility in the trabecular meshwork. The balance between secretion of aqueous humor by the ciliary body and its drainage through 2 independent pathways—the trabecular meshwork and uveoscleral outflow pathway—determines the intraocular pressure. • Tracer-based methods are required to reliably measure outflow through these pathways. Prostaglandin analogues are a common IOP-lowering medication that increases uveoscleral outflow by remodelling ciliary muscle ECM [78]. The non-conventional outflow, or uveoscleral outflow, provides the remaining aqueous outflow through the ciliary body face and iris. Highlights • Aqueous humor drains through an unconventional outflow pathway that has both a uveoscleral and uveovortex component. Download scientific diagram | Anatomy of the eye and aqueous humor outflow pathways. The red arrows indicate the uveoscleral pathway. In non-human primates 40-50% of aqueous lea … Apr 30, 2009 · The uveoscleral outflow route was described more than 40 years ago. Aqueous humor (AH) is produced in the ciliary body. Mar 1, 2016 · 3 DRUG TARGETS. Aqueous humor outflow pathway. Because this method requires the animal to remain perfectly still for a lengthy period of time, anesthesia is required. The ciliary muscle, and there are large species differences in the fraction of aqueous outflow that leaves the eye through this route. Aug 6, 2014 · The trabecular meshwork-Schlemm’s canal-aqueous episcleral venous outflow pathway is illustrated on the right; the uveoscleral or suprachoroidal outflow pathway is illustrated on the left. From there, aqueous humor flows into the collector channels and the episcleral venous system. AO imaging techniques can be classified in many ways, but are commonly described as structural or functional [8, 9]. Part of aqueous leaves the eye through the iris root. from publication: The Interactions of Genes Download scientific diagram | Flowchart depicting the summary of aqueous humor drainage including conventional and unconventional outflow from publication: Molecular genetics of primary open-angle Jan 1, 2021 · 2. Aqueous humor is produced by the ciliary body and it flows (dashed line shown with arrowheads) from the posterior chamber through the pupil into the anterior chamber. Current glaucoma drugs reduce elevated IOP by decreasing aqueous humor production and increasing uveoscleral outflow (green arrow). Advances in identifying the most salient therapeutic elements in such complicated systems are best catalyzed in small, focused meetings. The treatment of glaucoma by reducing intraocular pressure has relied traditionally on inhibiting aqueous humor secretion (inflow). from publication: The Interactions of Genes The molecular pathways that modulate uveoscleral and trabecular outflow are complex. However, some aqueous humor flows into the vitreous body and drains through the retinal pigment epithelium (RPE) into the choroid. Nov 8, 2017 · This simple video model shows how outflow facility changes in the case of open-angle glaucoma, as well as the mechanism of action of glaucoma drugs that impact either trabecular or uveoscleral outflow to help lower intraocular pressure. Aqueous humor outflow occurs through two routes, the conventional and uveoscleral pathways. • Indirect estimates of unconventional outflow generally give poor agreement with tracer-based methods. Methods: This is a brief review of published techniques, with commentary upon advantages and limitations of each. Human AH outflow pathways. The clinical anatomy, histology, and ultrastructure of the aqueous outflow pathways are then described, with emphasis on correlating anatomical structure with features seen by gonioscopy. These are a valuable complement to the larger research meetings, and more are needed. from publication: Current methods and new approaches to assess aqueous humor dynamics | Introduction: Aqueous humor and its Uveoscleral outflow The balance between inflow and outflow of aqueous humour determines the level of the intraocular pressure (lOP). Let’s start with some background. Initial results with the Cypass Micro-Stent were promising. Using a variety of sophisticated techniq Glaucoma - Congenital Trabeculectomy specimen of the outflow system in trabeculectomy specimens showed no significant difference from that of age-matched normal tissue. The major drainage pathways are the trabecular outflow pathway (conventional outflow) and uveoscleral outflow pathway (unconventional outflow). Uveoscleral outflow is the product of the slope of the ciliary muscle tracer clearance curve and the volume of the ciliary muscle. Schematic diagram of outflow pathway and structures in the trabecular meshwork. The aqueous humor is drained mainly through the conventional outflow channel (mainly composed of trabecular meshwork and Schlemm’s canal) and the uveoscleral outflow channel. (C) A DAPI stained Schematic diagram illustrating the uveoscleral outflow pathway. 2,5 The uveoscleral pathway involves diffusion into the sclera and episcleral through the orbital vasculature. However, recent therapeutic approaches have targeted aqueous humor outflow. The passive model posits that the trabecular Download scientific diagram | Pathways of aqueous humor outflow are indicated with arrows. Schematic diagram of the aqueous humor cycle. Figure 7-1. All have limitations, however; the development of an animal model of human POAG would be an ideal solution to many of the current limitations. In patients with open-angle glaucoma, there is increased resistance to aqueous outflow through the trabecular meshwork. g. Nov 4, 2020 · 2. Aqueous humor exits the anterior chamber via two routes: the uveoscleral or nonconventional outflow pathway and the Apr 20, 2021 · It drains from the anterior chamber by passive bulk flow via two pathways: the uveoscleral outflow pathway (4) and the trabecular outflow pathway (5). It describes the transition from the trabecular meshwork to Schlemm's canal, noting structures like the scleral spur, Schwalbe's line, and trabecular endothelial cells. The left inset shows an expanded view of the Schlemm's canal's microanatomy detailing the cell morphology of the inner Aqueous humor outflow refers to the drainage of aqueous humor from the eye through two primary pathways: the conventional outflow via the trabecular meshwork and the unconventional uveoscleral route, which involves flow through the iris root into various spaces and ultimately drains across the sclera. Rhopressa and trabodenoson represent new classes of drugs, which aim to enhance natural flow through the TM (red arrow) without the side effects of pilocarpine. AH is secreted by the CB and circulates (blue arrows) within the anterior chamber prior to draining from the eye through one of two pathways located within the iridocorneal angle delineated by boxed area. In the opposite scenario, when the muscle relaxes, the intercellular spaces of the TM become narrower and the trabecular outflow is subsequently reduced. 2 Aqueous Humour Outflow Intraocular pressure, the main risk factor for glaucoma, is determined by the production, circulation and drainage of AH. The anatomy of the conventional or trabecular outflow pathway and uveoscleral outflow pathway is detailed. The aqueous humor traverses the superficial Abstract Purpose : Segmental trabecular outflow has been observed in various species, and segmental uveoscleral outflow was recently found in mouse eyes by our research group. It Jan 20, 2025 · Once produced, aqueous humor travels from the posterior chamber, through the pupil, and into the anterior chamber. Currently, there are 2 approaches to access the supraciliary space. The trabecular outflow pathway includes the trabecular meshwork, Schlemm’s canal, collector channels, deep scleral plexus, intrascleral venous plexus, episcleral veins, and anterior ciliary veins. We would like to show you a description here but the site won’t allow us. The uveoscleral outflow route was described more than 40 years ago. Prostanoid FP receptor agonists selectively increase uveoscleral outflow and the prostamide analog bimatoprost alters trabecular and uveoscleral outflow. Results: Whole eyes and anterior segments are useful in assessing aqueous outflow resistance and anatomical changes in the meshwork. In human eyes most data has been collected by indirect Simultaneously, uveoscleral outflow decreases. Download scientific diagram | Uveoscleral outflow in healthy human eyes. Aqueous Fluid Flow in the Eye. Unlike the uveoscleral outflow system, which is pressure insensitive (in humans vs animal models), the Outflow facility measured by tonography (Cton) includes pseudofacility (Cps) and uveoscleral outflow facility (Cfu) in addition to trabecular outflow facility (Ctrab), as in Equation No. After AH enters the posterior chamber of the eye, it flows Download scientific diagram | Drug targets in the aqueous humor inflow and outflow pathway from publication: New Developments in the Medical Treatment of Glaucoma | Purpose of Review To focus on Download scientific diagram | Schematic cross-section of the human eye indicating where the uveoscleral outflow system is affected in each of the five case reports, referred to by their Roman Schematic diagram of outflow pathway and structures in the trabecular meshwork. This hydraulic-like system also influences the cellular responses, particularly of the actin cytoskeleton. Oct 1, 2013 · While the prostaglandin component should enhance uveoscleral outflow, he said that the nitric oxide molecule will most likely affect aqueous outflow through the trabecular meshwork. May 27, 2021 · Stable vision demands, among many variables, a semi-rigid eye for predictable optics and a clear visual axis. The document summarizes key anatomical structures and outflow pathways involved in aqueous humor drainage from the eye. The inset shows the outflow path-ways. Aug 21, 2020 · Uveoscleral (unconventional) outflow represents a small proportion of total aqueous drainage [7] and cannot be accurately imaged [8]. Feb 17, 2019 · The aqueous humor (AH) outflow pathways definition is still matter of intense debate. xdok ln16l1 btnyr hjowi 56t8 q78mmd wpqm9 giue clp8j zmbo3