• Written By:

    In this study, researchers assessed the reporting of complications in glaucoma surgical trials and developed a classification system for complication severity.

    Study design

    The systematic review identified 47 randomized controlled trials involving trabeculectomy or aqueous shunts published between January 2010 and July 2017. Quality of reporting complications was assessed according to the Consolidated Standards of Reporting Trials (CONSORT). A Delphi survey of 41 glaucoma experts was used to generate a consensus grading system for complications severity.


    Almost all of the trials reported the frequency of adverse events (91.5%) and the timing of the collection (93%), but many did not quantify severity (21%). Reporting participant withdrawals due to adverse events (6%) and subgroup analyses of harm (6%) were also uncommon.

    A trabeculectomy and tube shunt complication severity consensus was developed, grading severity from 1 (no harm) to 10 (permanent vision loss/painful eye). The most severe events included permanent loss of vision (hand motion or worse) and endophthalmitis. Mild events included transient loss of vision, early post-operative low IOP (5 mm Hg or less), small layered hyphema, transient corneal edema and anterior serous choroidal detachment.


    Defining and ranking the severity of surgical adverse events can be somewhat subjective and relies on group consensus. This tool will be useful for comparing adverse events caused by trabeculectomy or tube shunts but needs to be modified for other common glaucoma surgeries, particularly MIGS procedures. Finally, the complication severity is from the physician’s perspective, but the patient's perspective may be different.

    Clinical significance

    There were no validated instruments to report the severity of glaucoma surgery complications prior to this review. Once studies begin to consistently define and report the severity of adverse events, it may facilitate better, informed decision making in glaucoma trials.