XEN ® Gel Stent for management of chronic open angle glaucoma: A review of the literature.

PURPOSE: The purpose of this study was to analyze the change in intraocular pressure (IOP) and glaucoma medications using the XEN® Gel Stent as a solo procedure or in association with phacoemulsification in patients with chronic open angle glaucoma (OAG).

METHODS: We included cohort studies with at least one year of follow-up in patients with primary open angle glaucoma (POAG), pseudo-exfoliative glaucoma (PXG) or pigmentary glaucoma (PG) who received a XEN® gel stent. The main outcome measure was IOP reduction at 12 months follow-up. Secondary outcomes were the decrease in glaucoma medications 12 months after surgery, frequency and type of postoperative interventions and complication rate.

RESULTS: A total of 8 case series published between 2016 and 2018 were included; six were prospective studies, and two were retrospective. There was no randomized controlled trial. The data concerned a total of 958 eyes of 777 patients. The various studies showed a mean IOP at 12 months between 13 and 16mmHg, which represented an IOP reduction between 25 and 56% (mean: 42%). This decrease was associated with a reduction in glaucoma medications in all studies. The decrease in IOP was significantly greater in XEN® implantation as a stand-alone procedure (44%) than in combined surgery (32%) (P<0.05). Transient hypotony (< 1 month) (3%), choroidal detachment or choroidal folds (1.5%), hyphema (1.9%), bleb leak (1.1%) and shallow anterior chamber (1.1%) were the most frequent complications. As for severe complications, four cases of malignant glaucoma (0.4%) and one case of retinal detachment have been reported. In the follow-up period, needling has been required in 32% of cases, and a total of 55 eyes (5.7%) required repeat filtering surgery or cyclodestructive procedure.

CONCLUSION: XEN® Gel Stent appears effective for reducing IOP and the number of medications in OAG patients within 1 year postoperatively with an acceptable safety profile. However, vigilant postoperative follow-up and frequent postoperative maneuvers are required.