The implantation of a Xen gel Microstent and a Kahook Dual Blade (KDB) goniotomy is both safe and effective on their own, although the implantation of a Xen gel Microstent required more interventions postoperatively and was successful at a lower intraocular pressure threshold. Examining the efficacy of KDB goniotomy against Xen Gel Microstent implantation as a stand-alone procedure for treating moderate to severe glaucoma. One-center retrospective case series comparing 75 eyes treated with Xen Gel Microstent implantation alone versus eyes treated with KDB goniotomy. Primary outcomes included changes in intraocular pressure (IOP), glaucoma medication dose, surgical success, and complications. Definitions of surgical success included intraocular pressure (IOP) less than 21 mm Hg and IOP less than 18 mm Hg, with or without glaucoma drugs and without additional glaucoma surgery. After undergoing surgery, subjects were monitored for a minimum of 2 years. 

Both the Xen Gel Microstent and KDB goniotomy groups had similar mean IOP at baseline (23.7±8.4 and 25.9±7.9 mm Hg, respectively, P=0.32). Xen Gel Microstent resulted in a mean IOP of 14.7±3.2 mm Hg (a 32.7% decrease from baseline, P=0.018) and KDB goniotomy resulted in a mean IOP of 16.7±3.2 mm Hg (a 40.4% decrease from baseline, P=0.049) at 24 months post-surgery. There was no difference in mean IOP between the 2 treatment groups 24 months after surgery, despite a statistically significant decrease in IOP within the first month following Xen Gel Microstent implantation (P=0.416). The percentage of improvement in intraocular pressure (IOP) from preoperative levels was not substantially different between the 2 groups at 24 months after surgery. After 24 months, patients who had undergone Xen Gel Microstent implantation reduced their glaucoma medication use by 1.69 drops (P=.008), while those who had undergone KDB goniotomy reduced their use by 1.67 drops (P=0.038). Both groups saw similar rates of postoperative complications that did not threaten their patients’ eyesight (P=0.550). 

Needling was administered in 21 (37.5%) eyes in the Xen Gel Microstent group, and Nd:YAG goniopuncture was performed in 1 (5.6%) eye after KDB goniotomy, however, these interventions were not included with problems. The rate of success for surgery was similar between the 2 groups when the intraocular pressure threshold was less than 21 mm Hg (P=0.66).  There was a statistically significant improvement in surgical success rates between Xen Gel Microstent implantation and KDB goniotomy at a lower IOP threshold (<18 mm Hg; P=0.001). The intraocular pressure (IOP) of patients with moderate to severe glaucoma can be lowered by either KDB goniotomy or Xen Gel Microstent implantation alone. Success with the Xen Gel Microstent was stronger at lower IOP levels, but it was also related to a higher frequency of postoperative treatments.