To evaluate the standards of harm reporting for glaucoma surgical trials and to develop a classification system for reporting surgical complication severity.

Systematic review and Delphi consensus method.

Systematic review of glaucoma surgical trials published from January 2010 until July 2017 with a quality assessment against the CONSORT checklist for harm. A Delphi method was employed to generate consensus grading (interquartile range ≤ 2) among international glaucoma experts (n = 43) on severity of glaucoma surgical complications, and specifically for trabeculectomy and aqueous shunt complications, from 1 (no clinical significance) to 10 (most severe complication).

Forty-seven studies were eligible. The items of the CONSORT checklist for harm that were most frequently missing were use of a validated instrument to report severity (0%), withdrawals due to harm, and subgroup analyses, both reported in 3 publications (6.4%). Most glaucoma experts participating in the Delphi process (80%) completed the second round, and consensus was achieved for all but 1 complication. The least severe complications (graded 2) were “transient loss of vision,” “early low intraocular pressure,” “choroidal detachment anterior to equator,” “small layered hyphema < 1 mm,” and “increased lens opacity not clinically significant.” The most severe complications (graded 10) were “endophthalmitis” and “permanent severe loss of vision (hand movements or worse).”

Glaucoma surgical randomized controlled trials report frequency of complications, but their severity is rarely reported. The quality of harm reporting is poor. We propose the use of a newly developed system of classification for assessing the severity of surgical complications based on consensus.