scholarly journals Morphological changes in the trabecular meshwork and Schlemm’s canal after treatment with topical intraocular pressure-lowering agents

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ji-Hye Park ◽  
Hyun Woo Chung ◽  
Eun Gyu Yoon ◽  
Min Jung Ji ◽  
Chungkwon Yoo ◽  
...  
Keyword(s):  
Intraocular Pressure ◽  
Trabecular Meshwork ◽  
Morphological Changes ◽  
Open Angle Glaucoma ◽  
Anterior Segment ◽  
Schlemm’S Canal ◽  
Schlemm's Canal ◽  
Before And After ◽  
Treatment Naïve ◽  
Aqueous Outflow

AbstractGlaucoma treatment is usually initiated with topical medication that lowers the intraocular pressure (IOP) by reducing the aqueous production, enhancing the aqueous outflow, or both. However, the effect of topical IOP-lowering medications on the microstructures of the aqueous outflow pathway are relatively unknown. In this retrospective, observational study, 56 treatment-naïve patients with primary open-angle glaucoma were enrolled. Images of the nasal and temporal corneoscleral limbus were obtained using anterior segment optical coherence tomography (AS-OCT). The conjunctival vessels and iris anatomy were used as landmarks to select the same limbal area scan, and the trabecular meshwork (TM) width, TM thickness, and Schlemm’s canal (SC) area were measured before and after using the IOP-lowering agents for 3 months. Among the 56 patients enrolled, 33 patients used prostaglandin (PG) analogues, and 23 patients used dorzolamide/timolol fixed combination (DTFC). After 3 months of DTFC usage, the TM width, TM thickness, and SC area did not show significant changes in either the nasal or temporal sectors. Conversely, after prostaglandin analog usage, the TM thickness significantly increased, and the SC area significantly decreased (all P < 0.01). These findings warrant a deeper investigation into their relationship to aqueous outflow through the conventional and unconventional outflow pathways after treatment with PG analogues.

Stegmann Canal Expander for canaloplasty: A novel technique

2018 ◽  
Vol 28 (4) ◽  
pp. 472-478 ◽  
Author(s):  
Matthias C Grieshaber
Keyword(s):  
Intraocular Pressure ◽  
Trabecular Meshwork ◽  
Deep Sclerectomy ◽  
Specific Design ◽  
Schlemm’S Canal ◽  
Schlemm's Canal ◽  
Novel Technique ◽  
Dissection Technique ◽  
Aqueous Outflow ◽  
Outflow System

Introduction: The concept of canaloplasty is to increase aqueous egress through all structures that control the aqueous outflow, such as the trabecular meshwork, Schlemm’s canal, and collector channels, by viscomodulation and by placing of a suture stent into the canal. Clinical studies show canaloplasty to be safe and efficient in lowering the intraocular pressure; however, proper knotting of the tensioning suture is technically challenging and even impossible if circumferential cannulation cannot be achieved; furthermore, protrusion of the suture stent is a potential lifelong risk. Methods: The specific design of the Stegmann Canal Expander allows a permanent expansion of the canal and distension of the trabecular meshwork. Two expanders are implanted on either side of the surgically created ostium of Schlemm’s canal to treat half of the circumferential outflow system. This article describes the technique step by step, provides the clinician with surgical pearls, and highlights the management of adverse events. Results: Technically, implantation of the Stegmann Canal Expander is simple and does not require a long learning curve, compared to placing and knotting a tensioning suture. Most issues are related to the two-flap dissection technique (deep sclerectomy technique) and not to implantation of the Stegmann Canal Expander. Intraocular pressure reduction without medications to the low teens can be achieved. Conclusions: The Stegmann Canal Expander is a novel micro-device that has the potential to make canaloplasty a simplified, more controlled, and reproducible surgical procedure.

Three-dimensional confocal laser microscopy of fibronectin in normal and glaucomatous eyes

1991 ◽  
Vol 49 ◽  
pp. 402-403
Author(s):  
Annelies W. de Kater ◽  
R. Rand Allingham ◽  
Doug S. Bowman ◽  
Fredric S. Fay
Keyword(s):  
Fluid Flow ◽  
Intraocular Pressure ◽  
Aqueous Humor ◽  
Trabecular Meshwork ◽  
Open Angle Glaucoma ◽  
Confocal Laser ◽  
Schlemm’S Canal ◽  
Endothelial Lining ◽  
Schlemm's Canal ◽  
Specific Distribution

Aqueous humor exits the anterior chamber of the eye through the trabecular meshwork into Schlemm's canal, a vessel which drains into the systemic circulatory system. The aqueous humor crosses the endothelial lining of Schlemm's canal by means of focal invaginations which form pores and allow digress of fluid into the canal. The trabecular meshwork provides a resistance to fluid flow resulting in a physiologic intraocular pressure in normal eyes. The region adjacent to Schlemm's canal appears to be the site of highest resistance to fluid flow in both normal and glaucomatous eyes. In eyes with primary open angle glaucoma (POAG) the resistance to fluid flow through the trabecular meshwork is abnormally high, causing an elevated intraocular pressure (IOP), which can lead to irreversible damage of the optic nerve and blindness. A definitive morphologic correlate of this disease has not been discovered. Immunohistochemical studies localizing fibronectin in unfixed frozen sections of human eyes have shown elevated levels of fibronectin in the eyes with glaucoma, however the specific distribution of this protein has not been determined due to poor tissue preservation.

scholarly journals Anterior Segment Optical Coherence Tomography Signs of Local Dilatation Effect of a Micro-Stent on Schlemm’s Canal

2018 ◽  
Vol 10 (2) ◽  
pp. 184-187
Author(s):  
Kevin Gillmann ◽  
Giorgio Enrico Bravetti ◽  
Kaweh Mansouri ◽  
André Mermoud
Keyword(s):  
Optical Coherence Tomography ◽  
Trabecular Meshwork ◽  
Anterior Segment ◽  
Optical Coherence ◽  
Schlemm’S Canal ◽  
New Device ◽  
Schlemm's Canal ◽  
Canal Diameter ◽  
Trabecular Bypass

Introduction: The iStent inject® (Glaukos Corporation, CA, USA) is a relatively new device designed to be implanted ab-interno through the trabecular meshwork. This is, to the best of our knowledge, the first in-vivo description of a trabecular bypass device visualised with anterior segment optical coherence tomography (AS-OCT), and report of its structural effect on Schlemm’s canal. Case Report: A 74 year-old female patient suffering from long-standing primary open-angle glaucoma and nuclear sclerosis underwent cataract surgery combined with the implantation of two iStent injects®. Surgery was uncomplicated and achieved intraocular pressure (-1 mmHg) and medication (-2 molecules) reduction at 6 months. Under AS-OCT (Spectralis OCT, Heidelberg Engineering AG, Germany) the stent appears as a 300 μm long hyper reflective hollow device within the trabecular meshwork. Approximately a third of it protruded into the anterior chamber. Profound OCT signal loss was notable within the shadow of the device. A second AS-OCT section 500 μm beside the microstent shows a markedly dilated Schlemm’s canal, with a major diameter of 390 μm. Discussions: This report confirms that AS-OCT is a suitable technique to assess microstent positioning, and provides a first report on the in-vivo appearance of a functioning stent. It also indicates that iStent injects® could have a tangible effect on adjacent portions of Schlemm’s canal with, in this case, a 220% increase in canal diameter compared to the observed average (122 μm). This suggests the IOP-lowering effect of trabecular bypass devices could rely on a  dual mechanism involving Schlemm’s canal dilatation.

scholarly journals Suture Distension of Schlemm’s Canal in Canaloplasty: An Anterior Segment Imaging Study

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Livia M. Brandao ◽  
Andreas Schötzau ◽  
Matthias C. Grieshaber
Keyword(s):  
Intraocular Pressure ◽  
Anterior Segment ◽  
Imaging Study ◽  
Schlemm’S Canal ◽  
Schlemm's Canal ◽  
Anterior Segment Imaging ◽  
The Difference ◽  
Cup To Disc Ratio

Purpose. The object of this study was to investigate the role of the suture stent regarding its impact on reduction of intraocular pressure (IOP) in canaloplasty based on the distension of the inner wall of Schlemm’s canal.Methods. Nineteen glaucoma patients who underwent canaloplasty with successful positioning of the tensioning suture were included. The measurements were analyzed using linear mixed models, with the means adjusted to IOP, age, cup-to-disc ratio, and time of follow-up.Results. Mean follow-up time was 27.6 months (SD 10.5). Mean intraocular pressure (IOP) was 24.6 mmHg (SD 5.29), 13.8 (SD 2.65), and 14.5 (SD 0.71) before surgery, at 12 months, and at 36 months after surgery, respectively. 57.9% of patients had no medication at last evaluation. Differences and variations of measurements between the devices over a time of 12 months were not significant (p= 0.15 to 0.98). Some angles of distension associated with the suture stent inside SC were predictive for IOP reduction (p< 0.03 to < 0.001), but not for final IOP (p= 0.64 to 0.96).Conclusion. The angles of the inner wall of Schlemm’s canal generated by the suture stent were comparable between OCT and UBM and did not change significantly over time. There was a tendency towards a greater distension of Schlemm’s canal, when the difference was larger between pre- and postoperative IOP, suggesting the tensioning suture may contribute to IOP reduction.

A Randomized Trial of a Schlemm's Canal Microstent with Phacoemulsification for Reducing Intraocular Pressure in Open-Angle Glaucoma

Ophthalmology ◽  
2015 ◽  
Vol 122 (7) ◽  
pp. 1283-1293 ◽  
Author(s):  
Norbert Pfeiffer ◽  
Julian Garcia-Feijoo ◽  
Jose M. Martinez-de-la-Casa ◽  
Jose M. Larrosa ◽  
Antonio Fea ◽  
...  
Keyword(s):  
Intraocular Pressure ◽  
Randomized Trial ◽  
Open Angle Glaucoma ◽  
Open Angle ◽  
Schlemm’S Canal ◽  
Schlemm's Canal

scholarly journals Influence of Exercise on Intraocular Pressure, Schlemm's Canal, and the Trabecular Meshwork

2016 ◽  
Vol 57 (11) ◽  
pp. 4733 ◽  
Author(s):  
Xiaoqin Yan ◽  
Mu Li ◽  
Yinwei Song ◽  
Jingmin Guo ◽  
Yin Zhao ◽  
...  
Keyword(s):  
Intraocular Pressure ◽  
Trabecular Meshwork ◽  
Schlemm’S Canal ◽  
Schlemm's Canal

scholarly journals New Therapeutic Targets for Intraocular Pressure Lowering

2013 ◽  
Vol 2013 ◽  
pp. 1-14 ◽  
Author(s):  
A. Rocha-Sousa ◽  
J. Rodrigues-Araújo ◽  
Petra Gouveia ◽  
João Barbosa-Breda ◽  
S. Azevedo-Pinto ◽  
...  
Keyword(s):  
Intraocular Pressure ◽  
Trabecular Meshwork ◽  
Open Angle Glaucoma ◽  
Anterior Segment ◽  
Matrix Remodeling ◽  
New Agents ◽  
Uveoscleral Outflow ◽  
Pressure Lowering ◽  
Cytoskeleton Disruption ◽  
Trabecular Outflow

Primary open-angle glaucoma (POAG) is a leading cause of irreversible and preventable blindness and ocular hypertension is the strongest known risk factor. With current classes of drugs, management of the disease focuses on lowering intraocular pressure (IOP). Despite of their use to modify the course of the disease, none of the current medications for POAG is able to reduce the IOP by more than 25%–30%. Also, some glaucoma patients show disease progression despite of the therapeutics. This paper examines the new described physiological targets for reducing the IOP. The main cause of elevated IOP in POAG is thought to be an increased outflow resistance via the pressure-dependent trabecular outflow system, so there is a crescent interest in increasing trabecular meshwork outflow by extracellular matrix remodeling and/or by modulation of contractility/TM cytoskeleton disruption. Modulation of new agents that act mainly on trabecular meshwork outflow may be the future hypotensive treatment for glaucoma patients. There are also other agents in which modulation may decrease aqueous humour production or increase uveoscleral outflow by different mechanisms from those drugs available for glaucoma treatment. Recently, a role for the ghrelin-GHSR system in the pathophysiology modulation of the anterior segment, particularly regarding glaucoma, has been proposed.

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