Abstract:  Objective  To evaluate the efficacy and safety of XEN gel stent implantation in the treatment of advanced primary glaucoma. Design Retrospective case series. Participants From March 2022 to December 2023, 29 patients (33 eyes) with advanced primary glaucoma underwent consecutive XEN gel drainage tube implantation in Beijing Aier-Intech Eye Hospital. There were 16 cases (19 eyes) in the XEN group and 13 cases (14 eyes) in the Phaco combined XEN group. Method The patient's medical records were reviewed. Main Outcome Measures Visual acuity, intraocular pressure (IOP), number of IOP-lowering drugs, surgical success rate, and postoperative complications. Results  For all patients preoperative IOP，number of IOP-lowering medications and visual acuity (LogMAR) were 25.0 (IQR: 19.0, 34.0) mmHg, 4 (IQR: 3, 4) medications and 0.4 (IQR: 0.9, 0.2), respectively. At 1 year postoperatively, the IOP, mean IOP reduction, number of IOP-lowering medications, surgical success rate and visual acuity were 13.0 (IQR: 11.0, 16.0) mmHg, 46.0%, 0 (IQR: 0, 0) medications, 80.7% (25/31) and 0.3 (IQR: 1.0, 0.1), respectively. In the XEN group, preoperative IOP, number of IOP-lowering medications and visual acuity (LogMAR) were 26.0 (IQR: 19.0, 30.0) mmHg, 4 (IQR: 2, 4) and 0.2 (IQR: 0.7, 0.1), respectively. At 1 year postoperatively, the IOP, mean IOP reduction, number of IOP-lowering medications, surgical success rate and visual acuity (LogMAR) were 13.0 (IQR: 10.0,15.0) mmHg, 57.7%、0 (IQR: 0, 2) medications, 82.4% (14/17) and 0.3 (IQR: 0.7, 0.1) . In the PhacoXEN group, preoperative IOP, number of IOP-lowering medications, and visual acuity (LogMAR) were 24.5 (19.9, 32.0) mmHg, 3.5 (IQR: 3, 4) medications, and 0.7 (IQR: 2.0, 0.3), respectively. At 1 year postoperatively, the IOP, mean IOP reduction, number of IOP-lowering medications, surgical success rate, and visual acuity (LogMAR) were 13.0 (IQR: 12.0, 16.0) mmHg, 57.1%, 0 (IQR: 0, 0) medications, 78.6% (IQR: 11/14), and 0.3 (IQR: 1.0, 0.2), respectively.  There was no statistically significant difference in the surgical success rate at 1 year between the XEN and PhacoXEN groups (χ2=0.45，P=0.9299). Complications included hyphema (12.1%, 4/33), shallow anterior chamber (21.2%, 7/33), choroidal detachment (12.1%, 4/33), hypotony maculopathy (3.0%, 1/33), and blebitis (3.0%, 1/33), all managed conservatively. Bleb needling was required in 39.4% (13/33) of cases, significantly higher in the PhacoXEN group (50%, 7/14) than in the XEN group (31.5%, 6/19). No complications such as stent migration, exposure, or endophthalmitis occurred. Conclusion The results of the one-year follow-up with a small sample size in this study show that XEN gel stent implantation demonstrates favorable clinical efficacy and safety in advanced primary glaucoma, with comparable outcomes between standalone and combined procedures. However, the PhacoXEN group exhibited a higher rate of postoperative bleb needling.

Key words: Glaucoma/surgery, XEN gel stent