Costa 2004.

Methods	Study design: parallel group, randomized controlled trial Number randomized: 60 eyes of 60 participants Exclusions after randomization: 28 eyes of 28 participants lost to follow‐up at 12 months Number analyzed: 32 eyes of 32 participants at 12 months Unit of analysis: participant (one study eye per participant) Handling of missing data: participants lost to follow‐up were excluded from the analysis Sample size calculation: not reported
Participants	Country: Brazil, Canada, Scotland, USA Mean age: 62 years Gender: 36 (60%) men and 24 (40%) women Inclusion criteria: uncontrolled glaucoma requiring glaucoma drainage device implantation Exclusion criteria: younger than 18 years of age; learning difficulties; mental illness; dementia; unconsciousness or severe illness Equivalence of baseline characteristics: age, race, lens status, prior glaucoma surgery and IOP similar in the two groups at baseline Diagnoses in participants: primary open‐angle glaucoma; neovascular glaucoma; congenital glaucoma; traumatic glaucoma; inflammatory and steroid‐induced glaucoma; glaucoma following penetrating keratoplasty; aphakic glaucoma
Interventions	MMC group (n = 34): Ahmed valve implant with 0.5 mg/mL solution of MMC placed on the epislcera, under the conjunctiva and Tenon's capsule at the site for implant plate for 5 minutes No MMC group (n = 26): Ahmed valve implant with topical application of BSS using a soaked sponge on the episclera at site for implant plate for 5 minutes
Outcomes	Outcomes (primary and secondary outcomes not differentiated): mean IOP; surgical success, defined as 1) postoperative IOP between 6 and 21 mmHg with or without anti‐glaucoma medications or 2) IOP reduction of at least 30% relative to preoperative values; best‐corrected visual acuity; number of anti‐glaucoma medications; complications Length of follow‐up: postoperative day 1, weeks 1 and 2, months 1, 3, 6, 12, and 18
Notes	Study period: not reported Trial registration: not reported Funding and conflicts of interest: "The authors have no commercial interest in the products mentioned in the text".
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Method of sequence generation not reported
Allocation concealment (selection bias)	Unclear risk	Allocation concealment not reported
Masking of participants and personnel (performance bias)	Unclear risk	Masking of participants and personnel not reported
Masking of outcome assessment (detection bias)	Unclear risk	Masking of outcome assessors not reported
Incomplete outcome data (attrition bias) All outcomes	High risk	28/60 (47%) participants did not complete one year of follow‐up.
Selective reporting (reporting bias)	Unclear risk	No protocol or trial registry record available to compare outcomes
Other bias	Low risk	None identified