Comparison of XEN45 Gel Stent Outcomes in Glaucoma: Ab Externo Open-Conjunctiva Approach with Ologen vs. Ab Interno Closed-Conjunctiva Approach

<b>Background/Objectives:</b> This study evaluated the efficacy and safety of the ab externo open-conjunctiva (AEO) approach with adjunctive Ologen collagen matrix (OCM) compared to ab interno closed-conjunctiva (AIC) techniques for XEN45 gel stent implantation in patients with refractory open-angle glaucoma. The goal was to determine whether the AEO with OCM approach offers advantages in intraocular pressure (IOP) control and postoperative outcomes. <b>Methods:</b> A retrospective, comparative case series was conducted on 76 eyes from 76 patients with open-angle glaucoma who underwent XEN45 implantation between 2017 and 2022 at a single tertiary center. The patients were divided into Group 1 (AEO with OCM, n = 47) and Group 2 (AIC, n = 29). Postoperative IOP, the number of glaucoma medications, surgical complications, bleb revisions, and failure rates were recorded over 12 months. The AEO technique, supported by OCM, was assessed for its potential to reduce postoperative fibrosis and improve long-term outcomes. <b>Results:</b> Both groups experienced significant IOP reductions over time compared to baseline. However, Group 1 had superior outcomes, requiring fewer glaucoma medications postoperatively (<i>p</i> < 0.05), and demonstrated lower rates of complications (10.6% vs. 31.0%, <i>p</i> = 0.026) and bleb revisions (8.5% vs. 34.5%, <i>p</i> = 0.005). Kaplan-Meier survival analysis showed significantly greater cumulative surgical success in Group 1 compared to Group 2 (<i>p</i> < 0.001). <b>Conclusions:</b> The AEO with OCM approach to XEN45 implantation may provide improved safety and efficacy compared to the AIC approach. It appears to be beneficial in minimizing postoperative fibrosis, reducing the medication burden, and lowering complication and failure rates. Prospective randomized trials are needed to validate these findings.