Tube Versus Trabeculectomy IRIS Registry 1-Year Composite Outcome Analysis with Comparisons to the Randomized Controlled Trial

Published:February 28, 2021DOI:


      • TVT IRIS Registry 1-year composite outcome results differ from those of the TVT RCT.
      • TVT IRIS Registry tube and trabeculectomy failure rates are not significantly different.
      • Trabeculectomy failure rates are not significantly different between the 2 TVT cohorts.
      • Tube failure rates are significantly higher in the TVT IRIS Registry than in the TVT RCT.
      • Reasons for failure rates may be non-Baerveldt tubes, greater severity, or differences in clinical practice.


      This study compared 1-year results for the composite treatment outcome from the Tube Versus Trabeculectomy (TVT) randomized controlled trial (RCT) to those from an IRIS (Intelligent Research In Sight) Registry cohort of analogous eyes.


      Retrospective clinical study with comparison to an RCT.


      Subjects’ eyes in the IRIS Registry received either a glaucoma drainage implant (tube) or underwent trabeculectomy after a previous trabeculectomy and/or cataract extraction and had data for 1-year follow-up analyses.


      Eyes were classified as failing if they had hypotony (intraocular pressure (IOP) ≤5 mm Hg) or inadequate IOP control (IOP >21 mm Hg or not reduced at least 20% below baseline) on 2 consecutive follow-up visits after 3 months, a reoperation for glaucoma, or no light perception vision and as successful otherwise. Failure risk was compared by treatment, demographic, and clinical variables and was compared to analogous failure risks from the TVT RCT.


      The TVT IRIS Registry cohort included 419 eyes, 236 tube eyes (56.3%) and 183 trabeculectomy eyes (43.7%). In this cohort, there was no significant failure risk difference (12.3% for tube eyes and 16.4% for trabeculectomy eyes, P = 0.231). Comparing the studies, there was a significantly greater risk of failure in the TVT IRIS Registry tube eyes than in the TVT RCT tube eyes (3.8%; P <.001). Reasons for treatment failure included reoperations for glaucoma (none in the TVT RCT at 1 year).


      Our results were different from those in the TVT RCT. Possible reasons include non-Baerveldt tubes, greater severity among tube eyes, and practice patterns that reflect real-world data, which are different than those in RCTs.
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