Standalone XEN45 Gel Stent implantation in the treatment of open-angle glaucoma: A systematic review and meta-analysis

The XEN45 Gel Stent (Allergan Inc., Irvine, CA) allows the drainage of aqueous into the sub-conjunctival space, through a minimally-invasive approach. This systematic review and meta-analysis evaluates its intraocular pressure (IOP)-lowering efficacy and complications in the treatment of open-angle glaucoma. Fourteen studies comprising 963 eyes were included. IOP decreased significantly (P < 0.001) across all timepoints (1 day, 1 week, 1, 3, 6, 12, 18, and 24 months) with a mean decrease of 7.44 mm Hg (95%CI:4.91-9.97) at 24 months. IOP-lowering medications decreased significantly (P < 0.001) across all timepoints (1 week, 1, 3, 6, 12, 18, 24 months) with a mean reduction of 1.67 medications (95%CI:1.28-2.06) at 24 months. Numerical hypotony occurred in 39% (95%CI:14%-67%) and stent exposure in 1% (95%CI:0%-2%) of eyes. 38% (95%CI:30%-46%) of eyes required at least one postoperative needling, with an average of 0.6 (95%CI:0.37-0.81) needlings per eye. Standalone XEN45 Gel Stent implantation is effective in lowering IOP in open-angle glaucoma. Transient numerical hypotony is the most common postoperative complication. Sight-threatening complications are rare. Postoperative needling may be required to maintain IOP-lowering outcomes; however, the overall quality of current evidence is low, with the need for more randomized controlled trials and outcomes measured with a clinically meaningful definition of success.