Stand-Alone Xen Gel Microstent Implantation Compared With Kahook Dual Blade Goniotomy

Precis: Both Xen gel Microstent implantation and Kahook Dual Blade (KDB) goniotomy are safe and effective as stand-alone procedures, but the Xen Gel Microstent was associated with more postoperative interventions and achieved higher success at a lower intraocular pressure threshold. Purpose: To evaluate outcomes of stand-alone Xen Gel Microstent implantation compared with stand-alone KDB goniotomy for moderate to severe glaucoma. Methods: A retrospective, single-center, case-series analysis comparing outcomes of Xen Gel Microstent implantation and KDB goniotomy stand-alone cases in 75 eyes. Primary outcomes included intraocular pressure (IOP) reduction, glaucoma medication reduction, surgical success, and complications. Surgical success was defined using IOP<21 mm Hg and IOP<18 mm Hg thresholds, with or without glaucoma medications, and without further glaucoma surgery. Subjects were followed for at least 24 months after surgery. Results: Mean baseline IOP was comparable between the Xen Gel Microstent and KDB goniotomy groups (23.7 +/- 8.4 and 25.9 +/- 7.9 mm Hg, respectively, P=0.32). At 24 months after surgery, the mean IOP after Xen Gel Microstent was 14.7 +/- 3.2 mm Hg (32.7% reduction from baseline, P=0.018) and KDB goniotomy was 16.7 +/- 3.2 mm Hg (40.4% reduction from baseline, P=0.049). Although the mean IOP was significantly lower during the first month after Xen Gel Microstent implantation, no difference in mean IOP was observed between the 2 treatment groups at 24 months after surgery (P=0.416). At 24 months after surgery, the percent reduction of IOP from baseline was not significantly different between the 2 groups. The mean reduction of glaucoma medications from baseline at 24 months was 1.69 drops after Xen Gel Microstent implantation (P=.008) and 1.67 drops after KDB goniotomy (P=0.038). Postoperative complications were nonvision-threatening and were not significantly different between the 2 groups (P=0.550). Interventions not included with complications were needling performed in 21 (37%) of eyes in the Xen Gel Microstent group and Nd:YAG goniopuncture in 1 (5.6%) eye after KDB goniotomy. With an IOP threshold <21 mm Hg, surgical success was not significantly different between the 2 groups (P=0.06). At a lower IOP threshold (<18 mm Hg), surgical success was higher after Xen Gel Microstent implantation compared with KDB goniotomy (P=0.001). Conclusions: Both stand-alone Xen Gel Microstent implantation and KDB goniotomy can effectively and safely reduce IOP for moderate to severe glaucoma. The Xen Gel Microstent was associated with a higher need for postoperative interventions and achieved greater success at a lower IOP threshold.