Ab-Externo MicroShunt versus Trabeculectomy in Primary Open-Angle Glaucoma: One-Year Results from a 2-Year Randomized, Multicenter Study

N. Douglas Baker, Howard S. Barnebey, Marlene R. Moster, Michael C. Stiles, Steven D. Vold, Anup K. Khatana, Brian E. Flowers, Davinder S. Grover, Nicholas G. Strouthidis, Joseph F. Panarelli*, INN005 Study Group, Helena Beckers

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review


Purpose: To compare the effectiveness and safety of the MicroShunt versus trabeculectomy in patients with primary open-angle glaucoma (POAG). Design: One-year results from a 2-year, prospective, randomized, multicenter, noninferiority study (NCT01881425) conducted in the United States and Europe. Participants: Eligible patients were aged 40-85 years with intraocular pressure (IOP) >15 and 20% reduction in mean diurnal IOP from baseline (no medication washout) at year 1 without increasing the number of glaucoma medications. Secondary effectiveness end points at year 1 were the mean IOP change from baseline and requirement for postoperative intervention. Additional end points included glaucoma medication use and adverse events. Results: Overall, 395 (MicroShunt) and 132 (trabeculectomy) patients were randomized (mean Humphrey visual field mean deviation, -12.34 decibels [dB]). At year 1, probability of success was lower in the MicroShunt group compared with the trabeculectomy group (53.9% vs. 72.7%, respectively; P < 0.01). In the MicroShunt group, mean IOP +/- standard deviation decreased from 21.1 +/- 4.9 mmHg at baseline to 14.3 +/- 4.3 mmHg (-29.1%; P < 0.01) at year 1, with a mean of 0.6 +/- 1.1 glaucoma medications (baseline 3.1 +/- 1.0; P < 0.01). In the trabeculectomy group, mean IOP decreased from 21.1 +/- 5.0 mmHg to 11.1 +/- 4.3 mmHg (-45.4%; P < 0.01), with a mean of 0.3 +/- 0.9 glaucoma medications (baseline 3.0 +/- 0.9; P < 0.01). Postoperative interventions, including laser suture lysis, were reported in 40.8% (MicroShunt) versus 67.4% (trabeculectomy) of patients (P < 0.01). Reported incidence of transient hypotony was higher in the trabeculectomy group versus the MicroShunt group (49.6% vs. 28.9%; P < 0.01). Vision-threatening complications were uncommon and reported in 1.0% of MicroShunt versus 0.8% of trabeculectomy patients. Conclusions: Probability of success was lower with MicroShunt compared with trabeculectomy. Although reductions in IOP and glaucoma medications over 1 year were observed in both groups, the trabeculectomy group had a lower mean IOP on fewer medications. Ophthalmology 2021;128:1710-1721 (c) 2021 by the American Academy of Ophthalmology. This is an open access article under the CC BY-NC-ND license (http://creativecommons. org/licenses/by-nc-nd/4.0/).

Original languageEnglish
Pages (from-to)1710-1721
Number of pages12
Issue number12
Publication statusPublished - Dec 2021


  • Antifibrotic agents
  • Aqueous drainage devices
  • Glaucoma
  • Open-angle
  • Randomized controlled trial
  • Trabeculectomy
  • TUBE

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