Cutting Edge Glaucoma - Issue 2

26 • CUTTING EDGE - GLAUCOMA and − 1.7 (1.3) at month 12 and − 6.2 (4.9) mmHg and − 1.5 (1.4) at month 24, respectively (all P < 0.001). Mean medicated baseline IOP was reduced from 21.4 (3.6) to 14.9 (4.5) mmHg at 12 months and 15.2 (4.2) mmHg at 24 months, with similar results in both treatment groups. The clinical success rate was 67.6% at 12 months and 65.8% at 24 months. Overall, 51.1 (12 months) and 44.7% (24 months) of eyes were medication-free. The implant safety profile compared favora- bly with that published for trabeculectomy and tube shunts. Conclusions The gelatin implant effectively reduced IOP and medication needs over 2 years in POAG uncontrolled medically, with an acceptable safety profile. ClinicalTrials.gov registration number: NCT02006693 (registered in the U.S.A.). Keywords Glaucoma, Stent, Implant, Minimally invasive glaucoma surgery, Ab interno, XEN Introduction Topical therapy is the usual first-line treatment for open-angle glaucoma, but is often hampered by poor adherence [1, 2]. Traditional subconjunctival drainage procedures, such as trabeculecto- my and tube shunts, lower IOP most effectively but are relatively invasive and associated with both short- and longer-term complications that may result in significant loss of visual acuity [3–7]. Newer minimally invasive glaucoma surgery (MIGS) that permits earlier intervention is becom- ing part of the treatment armamentarium for glaucoma, providing a better safety profile than conventional approaches [8]. MIGS devices that can be implanted in conjunction with cataract surgery to facilitate aqueous drainage into Schlemm’s canal [9] or the supraciliary space [10] offer modest IOP lowering. An ab interno gelatin stent (XEN®45, Allergan plc, Dublin, Ireland) that also meets the criteria for MIGS [11] bypasses conventional outflow pathways that are known to be obstructed in primary open-angle glaucoma (POAG) by creating a connection between the anterior chamber and subconjunctival space [8], in a manner similar to the gold standard trab- eculectomy. The device is implanted ab interno, either as a stand-alone procedure or in combina- tion with cataract surgery, without conjunctival dissection. The hydrophilic gelatin implant swells and conforms to surrounding tissues, which helps maintain its position post-implantation. Results from studies demonstrating the IOP-lowering performance and safety of the gelatin implant at 1 year across a spectrum of glaucoma patients have been published [12–17]. The present study was designed to evaluate, over 2 years in typical clinical settings, the effectiveness of the gelatin implant as primary surgical intervention in reducing IOP and the number of topical IOP-lowering medications in patients with POAG uncontrolled on topical therapy. Methods Study Design This prospective, non-randomized, open-label, multicenter clinical study (ClinicalTrials.gov identifier: NCT02006693) was conducted between December 2013 and January 2017 in eight