LAUSR

AIM To assess the effectiveness and safety of the MicroShunt (formerly known as the MIDI-Arrow or InnFocus MicroShunt®), an 8.5-mm-long, 70-µm lumen controlled ab-externo glaucoma filtration surgery device made from poly(styrene-block-isobutylene-block-styrene) (SIBS), in patients with primary open-angle glaucoma (POAG). METHODS A 2-year, single-center, single-surgeon, non-randomized, adaptive feasibility clinical study (NCT01563237) was conducted in France from June 2011 to November 2016. Eligible patients were aged 18-85 years and had POAG inadequately controlled on maximum tolerated medical therapy with intraocular pressure (IOP) ≥18 and ≤40 mmHg. The MicroShunt was implanted ab externo with adjunctive use of Mitomycin C (0.2-0.4 mg/mL applied for 2-3 minutes), alone or in combination with cataract surgery. The primary effectiveness endpoints were the reduction in IOP relative to the preoperative value assessed at each postoperative visit and the measurement of success at years 1 and 2. The primary safety endpoint was the incidence of all procedure- and/or device-related adverse events (AEs) during the study. The secondary effectiveness endpoint was the mean number of glaucoma medications per patient, and the secondary safety endpoint was the incidence of glaucoma reoperation. RESULTS Sixty-one eyes from 61 patients underwent MicroShunt implantation. Mean IOP ± standard deviation (SD) was significantly reduced from 25.7 ± 6.1 mmHg at baseline (N = 61) to 15.8 ± 4.7 mmHg at year 1 (n = 58) and 16.5 ± 6.0 mmHg at year 2 (n = 52) (both p < 0.001). Overall success rates for patients achieving IOP ≥6 mmHg and <21 mmHg at year 1 and year 2 were 80.3% and 75.4%, respectively. Mean ± SD number of glaucoma medications per patient decreased significantly from 2.9 ± 1.1 at baseline to 0.6 ± 1.0 at year 1 (n = 58) and 1.0 ± 1.3 at year 2 (n = 52) (both p < 0.001). The most common procedure- and/or device-related AEs were investigator-reported increased IOP and hyphema. Four patients required reoperation. CONCLUSIONS In this study, sustained reductions in mean IOP and number of glaucoma medications from baseline were observed up to 2 years post surgery. No long-term, sight-threatening AEs were observed.