XEN® Gel Stent versus PRESERFLO™ MicroShunt for Open-Angle Glaucoma: A Systematic Review and Meta-Analysis with GRADE Certainty Assessment

Purpose To compare the efficacy, postoperative intervention burden, safety, and surgical success of the XEN® Gel Stent versus the PRESERFLO™ MicroShunt in adults with open-angle glaucoma using a PRISMA 2020-compliant systematic review and meta-analysis. Clinical relevance The XEN® Gel Stent and the PRESERFLO™ MicroShunt are increasingly adopted to reduce intraocular pressure and medication burden in open-angle glaucoma with less morbidity than conventional filtering surgery. Comparing their performance can help guide device selection. Methods PubMed/MEDLINE, Embase, Scopus, Web of Science, and CENTRAL were searched from inception through June 2026 for comparative studies evaluating XEN® versus PRESERFLO™ MicroShunt. Continuous outcomes were pooled as change-from-baseline mean differences (MD; XEN® minus PRESERFLO™) using REML random-effects models, whereas binary outcomes were pooled as odds ratios (OR; XEN®/PRESERFLO™) using Paule-Mandel random-effects models. Follow-up-duration subgroup analyses and a prespecified sensitivity-analysis framework were applied. Risk of bias was assessed using ROBINS-I V2 for non-randomized studies and a RoB 2-style framework for the randomized trial. Certainty of evidence was assessed using GRADE. Results Fourteen studies were included in the systematic review, and nine contributed to quantitative synthesis. IOP reduction, the primary efficacy outcome, did not differ significantly between devices at the latest available follow-up (MD 0.89 mmHg, 95% CI −0.21 to 1.99; P=0.1122; I²=30.0%; Low certainty). PRESERFLO™ was associated with higher study-defined surgical success (OR for XEN® versus PRESERFLO™ 0.46, 95% CI 0.30 to 0.70; P=0.0004; Low certainty) and a modestly greater reduction in medication burden (MD 0.35 medications, 95% CI 0.06 to 0.64; P=0.0165; Low certainty). Postoperative bleb-directed intervention was more frequent after XEN®, whether analysed as needling (OR 3.76, 95% CI 2.07 to 6.84; Moderate certainty) or as a composite of needling and/or open bleb revision (OR 2.75, 95% CI 1.82 to 4.16; k=7; Moderate certainty). Bleb revision alone, reoperation, and hypotony did not differ significantly. Pooled estimates were similar when complete and qualified or criterion-based success were analysed separately, and the principal conclusions were robust across sensitivity analyses. No formal test for subgroup differences by follow-up duration was statistically significant. Conclusions Current direct comparative evidence does not establish a significant difference in IOP reduction between XEN® Gel Stent and PRESERFLO™ MicroShunt at the latest available follow-up. PRESERFLO™ was associated with higher study-defined surgical success and fewer postoperative bleb-directed interventions, while the small medication advantage was statistically fragile. Certainty ranged from Moderate to Very low and was limited predominantly by non-randomized evidence.