Under flow testing, the XEN micro-fistula implant was able to maintain backpressure above numerical hypotony levels without the use of complex valve systems. This is due to the XEN implant's design, derived from the principles that dictate Newtonian fluids.

ImportanceThe transscleral XEN Glaucoma Gel Microstent (XEN‐GGM, Allergan Plc., Parsippany, New Jersey) is implanted by a minimally invasive ab interno technique.BackgroundThe present study aims to assess the long‐term clinical outcomes in patients after XEN‐GGM implantation.DesignThis prospective, non‐randomized, multi‐centred study was conducted in three countries (Austria, Canada and Germany).ParticipantsSixty‐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.MethodsVisits were planned at baseline, 6 months, 1, 2, 3 and 4 years postoperatively.Main Outcome MeasuresThe 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.ResultsMean 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 RelevanceThe 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.

Dr. Sheybani has received travel reimbursement from Aquesys, Inc. Dr. Ahmed is a paid consultant to Aquesys, Inc. No other author has a financial or proprietary interest in any material or method mentioned.