Four-year results of a minimally invasive transscleral glaucoma gel stent implantation in a prospective multi-centre study

Importance: The transscleral XEN Glaucoma Gel Microstent (XEN-GGM, Allergan Plc., Parsippany, New Jersey) is implanted by a minimally invasive ab interno technique. Background: The present study aims to assess the long-term clinical outcomes in patients after XEN-GGM implantation. Design: This prospective, non-randomized, multi-centred study was conducted in three countries (Austria, Canada and Germany). Participants: Sixty-four consecutive eyes of 64 patients with open angle glaucoma received the XEN-GGM (63 μm) without Mitomycin C. Thirty-five (55%) were solo procedures, and 29 (45%) were combined with cataract surgery. Methods: Visits were planned at baseline, 6 months, 1, 2, 3 and 4 years postoperatively. Main Outcome Measures: The main outcome measures were mean intraocular pressure (IOP), mean number of IOP lowering medication. Secondary outcome parameters were: visual acuity, visual fields and complete surgical failure (defined as presence of a secondary IOP lowering procedure or loss of light perception) at 4 years, postoperatively. Results: Mean best-medicated baseline IOP was 22.5 ± 4.2 mmHg and decreased significantly to 13.4 ± 3.1 mmHg 4 years postoperatively (−40%, n = 34, P < 0.001). Mean number of IOP lowering medication decreased significantly from 2.4 ± 1.3 preoperatively to 1.2 ± 1.3 (−50%, n = 34, P < 0.001) postoperatively. Visual field mean deviation showed no significant change between preoperative and postoperative examinations. Complete surgical failure rate per year was 10%. Conclusions and Relevance: The XEN-GGM resulted in lower IOP and a reduction in medications from baseline over 4 years of follow-up. There was no detectable decrease in visual fields over the study. The surgical failure rate is comparable to other filtration surgeries.