Glaucoma drainage devices / Dispositivos de drenagem para glaucoma

ABSTRACT Glaucoma drainage devices are important therapeutic options for cases of refractory glaucoma, in which trabeculectomy with antimetabolites has shown high risk of failure. There are devices with different sizes, designs and materials, and several studies have been conducted to test their safety and effectiveness. Despite known complications, their use has progressively increased in recent years, and they are the primary surgical option, in some situations. The aim of this review is to discuss the importance, mechanisms, biomaterials, results and complications of glaucoma drainage devices.

RESUMO Os dispositivos de drenagem para glaucoma são importante opção terapêutica em casos de glaucomas refratários, nos quais a trabeculectomia com antimetabólitos tem alta chance de falência. Há dispositivos com diferentes tamanhos, desenhos e materiais, e muitos estudos foram realizados para testar sua segurança e eficácia. Apesar de suas conhecidas complicações, seu uso tem aumentado progressivamente nos últimos anos, inclusive como primeira opção cirúrgica, em algumas situações. O objetivo desta revisão foi discutir a importância, os mecanismos, os biomateriais, os resultados e as complicações dos dispositivos de drenagem para glaucoma.

Clinical Outcomes of Ahmed Glaucoma Valve Implantation Using Tube Ligation and Removable External Stents

PURPOSE: To investigate the immediate and long-term outcomes of Ahmed glaucoma valve (AGV) implantation with silicone tube ligation and removable external stents. METHODS: This retrospective non-comparative study investigated the outcomes of AGV implantation with silicone tube ligation and removable external stents in 95 eyes (90 patients) with at least 12 months of postoperative follow-up. Qualified success was defined as an intraocular pressure (IOP) of or =6 mmHg regardless of anti-glaucoma medication. Those who required additional glaucoma surgery, implant removal or who had phthisis bulbi were considered failures. Hypotony was defined as an IOP of <6 mmHg. RESULTS: Mean IOP reduced from 37.1+/-9.7 mmHg preoperatively to 15.2+/-5.6 mmHg at 12 months postoperatively (p<0.001). Qualified success was achieved in 84.2% at 1 year. Hypotony with an IOP of <6 mmHg was seen in 8.4% and an IOP of <5 mmHg in 3.2% on the first postoperative day. No case of hypotony required surgical intervention. Suprachoroidal hemorrhage did not occur in this study. When stents were removed on the first postoperative day because of an insufficient IOP decrease, the mean IOP decreased significantly from 42.0 mmHg to 14.1 mmHg (p<0.001) after 1 hour. The most common complication was hyphema, which occurred in 17.9%. CONCLUSIONS: Hypotony-related early complications requiring surgical intervention were reduced by ligation and external stents in the tube. In addition, early postoperative high IOPs were managed by removing external stents. The described method can prevent postoperative hypotony after AGV implantation and showed long-term success rates comparable to those reported previously.

Recurrent Intraocular Pressure Elevation during Hemodialysis in a Patient with Neovascular Glaucoma

PURPOSE: To report a patient with symptomatic intraocular pressure (IOP) elevation in an eye with neovascular glaucoma (NVG) during hemodialysis. METHODS: Case report. RESULTS: Recurrent episodes of severe ocular pain and elevated IOP in the NVG eye were noted during hemodialysis in a 29-year-old man. The patient was recently diagnosed at our ophthalmology clinic with NVG due to central retinal vein occlusion. IOP was temporarily controlled after the Ahmed valve implantation. However, after the fibrous membrane developed and occluded the tip of the Ahmed valve, IOP elevation during hemodialysis recurred. Further treatments with intravenous mannitol, oral carbonic anhydrase inhibitor, topical antiglaumatic agents and subconjunctival 5-fluorouracil (5-FU) injections all failed to control relapsing pain and IOP elevation. Eventually, evisceration and hydroxyappatite implantation were performed. CONCLUSIONS: Physicians must be alert to the possibility of IOP elevation in glaucomatous eyes during hemodialysis.