Précis: 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.

Purpose: Our aim was to evaluate and compare the clinical outcomes after implantation of the silicone-plate (model FP7) and porous polyethylene-plate (model M4) Ahmed Glaucoma Valves. Patients and Methods: This was a prospective, multicenter, comparative series. A total of 52 eyes (52 patients) were treated with either the silicone or porous plate Ahmed Glaucoma Valve implant. Hypertensive phase was defined as intraocular pressure >21 mmHg during the first 3 months postoperatively. Success was defined as 5 mmHg ≤intraocular pressure ≤21 mmHg (with or without additional glaucoma medications), without loss of light perception and without additional glaucoma procedures. Patients were monitored for 1 year after surgery. Results: The pre-operative intraocular pressure was 29.9 ± 6.6 mmHg and 33.8 ± 10.5 in the silicone-plate and porous-plate groups, respectively (P = 0.118). At 12 months after surgery, the mean intraocular pressure was 13.6 ± 4.7 mmHg in the silicone-plate group and 17.9 ± 10.9 mmHg in the porous-plate group (P = 0.141). The mean number of glaucoma medications at 12 months was 1.64 ± 1.40 mmHg and 1.89 ± 1.54 mmHg in the silicone-and porous-plate groups, respectively (P = 0.605). Hypertensive phase was not significantly different in the two groups (50.0% of the silicone-plate and 57.7% of the porous-plate groups, P = 0.578). At 12 months after surgery, the percent success for the silicone-plate and porous-plate groups was 88.5% and 53.8%, respectively (P = 0.005). Complications were similar in the two groups. Conclusion: The porous-plate Ahmed Glaucoma Valve showed similar average intraocular pressure reduction compared with the silicone-plate model. At 12 months after surgery, there was a significantly lower success rate in the porous-plate compared with the silicone-plate group.

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