iStent trabecular micro-bypass stent for open-angle glaucoma

Abstract

Trabecular micro-bypass stents, commonly known as iStents, are micro-invasive glaucoma surgery (MIGS) devices used to treat open-angle glaucoma. Like other MIGS procedures that enhance trabecular outflow, the iStent lowers intraocular pressure (IOP) by creating a direct channel between the anterior chamber and Schlemm’s canal. iStents are typically implanted at the time of phacoemulsification for patients with open-angle glaucoma and visually significant cataracts. This review summarizes the published data regarding the efficacy, safety, and cost considerations of trabecular micro-bypass stents. Most studies found statistically significant reductions in mean IOP and ocular medication use after combined phacoemulsification with single or double iStent implantation. The devices were found to be very safe, with a safety profile similar to that of cataract surgery. Complications were infrequent, with the most common complications being temporary stent obstruction or malposition, which resolved with observation or secondary procedures. Future studies are needed to evaluate long-term outcomes, patient satisfaction, cost effectiveness, and expanded indications.

Systematic Literature Review of Clinical and Economic Outcomes of Micro-Invasive Glaucoma Surgery (MIGS) in Primary Open-Angle Glaucoma

“…The iStent, Hydrus, and CyPass devices generally have favorable safety profiles with few reported AEs. Hyphema is common with iStent and Hydrus, with rates of 19.04% for Hydrus and a few cases reported for iStent [ 52 , 53 ]. High rates of hyphema are unsurprising for these MIGS devices considering they are implanted into a highly vascular region.…”

“…High rates of hyphema are unsurprising for these MIGS devices considering they are implanted into a highly vascular region. Other harm and AEs reported with the iStent included stent malpositioning or occlusion early in the postoperative period, affecting 4–18% of cases [ 32 , 33 , 44 , 53 ]. Corneal erosion has also been reported in one study, attributed to repeated intraoperative gonioscopy [ 54 ]: these types of risks are only relevant for MIGS that require gonioscopy.…”

<p>Refractive outcomes after trabecular microbypass stent with cataract extraction in open-angle glaucoma</p>

“…The iStent (Glaukos, San Clemente, CA, USA), the first US Food and Drug Administration–approved MIGS device, is a trabecular microbypass stent designed to bypass the trabecular meshwork to augment physiological outflow to Schlemm’s canal and lower intraocular pressure (IOP) 6. The safety and efficacy of the iStent alone,7–9 as well as when combined with cataract surgery,10–13 has been well established in the literature.…”

A review of the iStent&reg; trabecular micro-bypass stent: safety and efficacy

“…The surgical technique for implanting the iStent has been thoroughly reviewed elsewhere; 5 , 10 we emphasize that there is a significant learning curve to obtaining an adequate gonioscopic view of the angle and proper placement of the device. Some of the difficulties with placement of the first-generation device have been alleviated in the design of the second-generation device.…”

“…This procedure is intended to lower IOP via direct cannulation of Schlemm’s canal in order to enhance aqueous outflow. Although trabecular micro-bypass surgery has been recently reviewed, 5 – 9 this paper provides an update on published data with a focus on safety and efficacy.…”