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Glaucoma Effects of Glaukos ® Trabecular Stent in the Treatment of Glaucoma Pedro Arriola-Villalobos, 1 Laura Morales-Fernández, 1 José M Martínez-de-la-Casa 2 and Julián García-Feijoó 3 1. Ophthalmology Unit, Clinico San Carlos Hospital Health Research Institute; 2. Ophthalmology Unit, Clinico San Carlos Hospital, Ophthalmology and Otorhinolaryngology Department, School of Medicine, Universidad Complutense, Clinico San Carlos Hospital Health Research Institute; 3. Ophthalmology Unit, Clinico San Carlos Hospital, Ophthalmology and Otorhinolaryngology Departament, School of Medicine, Ophthalmic Research Institute, Universidad Complutense, Clinico San Carlos Hospital Health Research Institute, Cooperative Research Network on Age-Related Ocular Pathology, Visual and Life Quality, Health Institute Carlos III Abstract Micro-invasive glaucoma surgery (MIGS) is gaining interest in very recent years, due to a better safety profile and good tensional results, often associated to cataract surgery. Glaukos iStent® is the only FDA-approved device for micro-invasive glaucoma surgery. It connects the anterior chamber to Schlemm´s canal by bypassing the trabecular meshwork, increasing the outflow facility. The Glaukos iStent is indicated for use in conjunction with cataract surgery for the reduction of intraocular pressure (IOP) in adult patients with mild to moderate open-angle glaucoma currently treated with ocular hypotensive medication. This article summarises the results of all the clinical and experimental studies published regarding iStent effectiveness and safety. Glaukos iStent, in conjunction with cataract surgery, is a safe and effective option in the treatment of open angle glaucoma, with a significant but modest IOP drop and a significant and more clinically relevant decrease in glaucoma medications, with no serious adverse events. Some aspects concerning the number of iStent used or other indications like ocular hypertension or secondary glaucoma remain under study, although good results in both clinical situations have been published. A new model of iStent has just been developed and its first clinical results are near to be published. Keywords Micro-invasive, glaucoma, surgery, iStent, cataract Disclosure: Julian García-Feijoó is a consultant to the Glaukos Corporation. The remaining authors have no conflicts of interest to declare. Received: 17 December 2012 Accepted: 20 January 2013 Citation: European Ophthalmic Review, 2013;7(1):10–3 Correspondence: Pedro Arriola-Villalobos, Ophthalmology Unit, Hospital Clinico San Carlos, C/Profesor Martin Lagos, s/n, 28040, Madrid, Spain. E: In very recent years there is an increasing interest on micro- invasive glaucoma surgery (MIGS) procedures. 1 Traditional ab externo glaucoma surgical procedures (e.g., trabeculectomy, tubes, deep sclerectomy) are associated with significant risks and complications, whereas MIGS procedures are associated with mild and less frequent side events and do not limit other surgical options in the future. Moreover, MIGS procedures have a more rational approach to the aetiology of glaucoma, because the trabecular meshwork is the site of resistance to aqueous humor outflow in primary open- angle glaucoma (POAG). Surgical procedures involving the anterior chamber angle, such as goniotomy and trabeculotomy, are usually indicated for congenital glaucoma. In adults, the healing response after these surgical procedures prevents an adequate and maintained hypotensive effect. Recently, alternative surgical procedures, such as silicone tubes, 2 Y-shaped bidirectional glaucoma tubes, 3 the trabectome 4 and the Hydrus, a three clock hour nitinol scaffold, 5 which focus on the anterior chamber angle have been proposed to reduce post-operative scarring. The purpose of these devices is to reduce intraocular pressure (IOP) by draining the aqueous humor through the collector channels. The Glaukos iStent ® (Glaukos Corporation, Laguna Hills, California) is a 0.5 x 0.25 x 1 mm L-shaped, heparin-coated stent made of titanium (see Figure 1). The stent was designed to connect the anterior chamber 10 to Schlemm’s canal by bypassing the trabecular meshwork, increasing the outflow facility and reducing the IOP. 6–8 Glaukos iStent has received FDA approval for the treatment of glaucoma in June 2012, being the only FDA-approved device for the treatment of mild to moderate open-angle glaucoma. Spiegel et al. described the surgical technique. 9 The stent is ideal for implantation combined to phacoemulsification and the surgery can be performed under topical anaesthesia. The angle is easier to visualise and the surgery is easier to perform in pseudophakic eyes. To achieve a successful surgical outcome, the most important step is to have clear visualisation of the angle by tilting the operating microscope 30 degrees and turning the patient’s head at least 45 degrees away from the surgeon. In combined surgery, when phacoemulsification has been completed and an intraocular lens has been inserted, the anterior chamber should be refilled with a cohesive viscoelastic. The surgical microscope and the patient´s head then are repositioned and the angle is visualised with a gonio lens placed on the cornea. Finally, the inserter is introduced into the anterior chamber and the stent is placed into Schlemm’s canal through the trabecular meshwork. The stent is implanted through a temporal approach in a nasal position. If two implants are used, one is placed inferonasally and the other superonasally. The stent should be parallel to the iris root with the rails located on the back wall of Schlemm’s canal (see Figure 2). © Touch ME dical ME dia 2013