Birt 1998.

Methods	Study design: parallel‐group randomized controlled trial Number randomized: 43 eyes of 43 participants total; 11 participants in trabeculectomy + MMC + Gelfilm® (Pfizer) group; 7 participants in trabeculectomy + MMC group; 11 participants in trabeculectomy + Gelfilm® (Pfizer) group; 14 participants in trabeculectomy group Exclusions after randomization: none reported Losses to follow‐up: none reported Unit of analysis: individual (1 eye per participant) Number analyzed: 43 participants total; 11 participants in trabeculectomy + MMC + Gelfilm® (Pfizer) group; 7 participants in trabeculectomy + MMC group; 11 participants in trabeculectomy + Gelfilm® (Pfizer) group; 14 participants in trabeculectomy group How were missing data handled?: no missing data Power calculation: not reported
Participants	Country: not reported Mean age: not reported Gender: not reported Inclusion criteria: not reported Exclusion criteria: not reported Equivalence of baseline characteristics: not reported
Interventions	Intervention 1: trabeculectomy + MMC + Gelfilm® (Pfizer) Intervention 2: trabeculectomy + MMC Intervention 3: trabeculectomy + Gelfilm® (Pfizer) Intervention 4: trabeculectomy Length of follow‐up: Planned: not reported Actual: 1 year
Outcomes	Primary and secondary outcomes not distinguished Outcomes, as reported: postoperative IOP, use of postoperative 5‐FU, and complications Intervals at which outcomes assessed: 1 year
Notes	Publication type: published abstract Funding sources: not reported Disclosures of interest: not reported Trial registry: not registered Study period: not reported Subgroup analyses: none reported Publication language: English Attempted to contact author, but unable to find contact information in abstract
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Random sequence generation was not reported
Allocation concealment (selection bias)	Unclear risk	Allocation concealment was not reported
Masking of participants and personnel (performance bias)	Unclear risk	Masking of participants and personnel was not reported
Masking of outcome assessment (detection bias)	High risk	Outcome assessors not masked as devices can be seen during eye examination
Incomplete outcome data (attrition bias) All outcomes	Low risk	All participants completed 1‐year follow‐up
Selective reporting (reporting bias)	Unclear risk	The protocol was not available and the authors did not define which outcomes and complications they were going to report
Other bias	Unclear risk	Did not report source of funding or conflict of interest The abstract did not have enough information