Efficacy and safety of Ab interno XEN gel implant after a failed filtering surgery

Purpose: To evaluate the efficacy and safety of Ab interno XEN gel stent in patients with open angle glaucoma who underwent a previous failed filtering surgery. Methods: A retrospective, observational, multi-centered and descriptive cohort study was conducted from January 2019 to February 2020 on patients with primary open angle glaucoma (POAG) who underwent XEN gel stent implant after a failed filtering surgical procedure. Main parameters evaluated were: changes in IOP measured with Goldmann applanation tonometer, number of anti-glaucomatous eye drops, postoperative complications, and necessity of further surgical procedures. The quantification of quality of life was obtained from the VFQ-25 questionnaire. A descriptive analysis based on pre- post- and intra-operative data was carried out. Results: In all patients included in the study (6 patients for a total of 7 eyes), IOP dropped during the follow up time. We found a mean percentage reduction of -41.5% at 9 months compared to the preoperative data (baseline). IOP lowered from 21.71 ± 4.64 mmHg to 9 ± 3,21 mmHg 1 day after the operation, 11 ± 3.21 at 1 week, 11.42 ± 1.81 mmHg at 1 month, 12.42 ± 3.10 mmHg at 3 months, 13.57 ± 3.45 at 6 months, 12.71 ± 1.79 at 9 months. In 71.4%, the procedure turned out to be complication free and only one case required needling of the bleb in order to achieve optimal intraocular pressure control. A total of 71.4% patients reached a medication free regimen with a percentage of reduction in the mean number of drugs needed of -88.9%. Conclusion: In our experience, XEN gel stent implant performed in Caucasian patients with POAG and a history of failed filtrating surgery, showed to be an effective and safe procedure.