Aim: To compare outcomes of ab interno XEN gelatin stent (Allergan, Dublin, Ireland) implantation vs trabeculectomy with mitomycin C (MMC). Materials and methods: A retrospective review was conducted of eyes that underwent standalone XEN implantation or trabeculectomy with MMC at a single institution from 2014 to 2019. Intraocular pressure (IOP), visual acuity, glaucoma medications, complications, and postoperative interventions were evaluated. The primary endpoint was the reduction in IOP at 6 months postoperatively. Secondary endpoints included the incidence of postoperative intervention and complications. Results: One hundred and seventy-nine eyes were included who underwent XEN (n = 90) or trabeculectomy (n = 89). The mean age was 74.5 ± 7.6 and 68.1 ± 8.2 years old for the XEN and trab groups, respectively (p < 0.001). Baseline IOP for XEN was 17.8 ± 6.0 vs 20.4 ± 9.0 mm Hg for the trab group (p = 0.03). At 6 months, mean IOP for XEN group was 13.5 ± 5.9 mm Hg, representing a 24.1% IOP reduction from baseline (p < 0.001) while mean for trab group was 10.8 ± 4.8 representing a 47% IOP reduction from baseline (p < 0.001). The mean IOP was 2.7 mm Hg lower in trab compared to the XEN group at 6 months (p < 0.003). The number of medications was reduced in both groups from 2.9 ± 1.1 and 3.1 ± 0.9 to 1.1 ± 2.3 and 0.8 ± 1.4 by 6 months postoperatively for XEN and trab groups, respectively (p < 0.001). Complication rates were low for both groups. The needling rate was 30% in XEN vs 7.9% in the trab group (p < 0.001), and 46.1% of eyes in the trab group underwent laser suture lysis. Additionally, IOP reduction and complication rates were similar following XEN in eyes receiving <40 or ≥40 μg of MMC. Conclusion: XEN implantation produces a substantial reduction in IOP with a favorable safety profile comparable to trabeculectomy. Careful postoperative bleb management is critical to obtain optimum outcomes, and higher MMC doses appear safe and may reduce needling rates. Clinical significance: This study confirms the safety and efficacy of XEN gelatin stent implantation in comparison to trabeculectomy with MMC.
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