Netland 2014.

Study characteristics
Methods	Study design: parallel‐group randomized controlled trial Country: USA Number randomized: 120 eyes of 120 participants total; 59 participants in trabeculectomy + MMC + Ex‐PRESS group; 61 participants in trabeculectomy + MMC group Exclusions after randomization: 1 participant randomized to receive treatment but was withdrawn prior to surgery because of thin sclera Losses to follow‐up: 6 participants total; 2 participants in trabeculectomy + MMC + Ex‐PRESS group; 4 participants in the trabeculectomy + MMC group Unit of analysis: individual (1 eye per participant) Number analyzed: 114 participants total; 57 participants in trabeculectomy + MMC + Ex‐PRESS group; 57 participants in trabeculectomy + MMC group How were missing data handled? 6 participants excluded from analysis Power calculation: a power of 80% to detect a 2 mmHg IOP difference between groups with a sample size of 60 participants in each group
Participants	Mean age: 69 years 69.4 years for trabeculectomy + MMC + Ex‐PRESS group 67.8 years for trabeculectomy + MMC group Gender 32/59 (54%) men and 27/59 (46%) women in trabeculectomy + MMC + Ex‐PRESS group 33/61 (54%) men and 28/61 (46%) women in trabeculectomy + MMC group Inclusion criteria: aged > 18 years; diagnosed with OAG (including POAG, PEXG, and pigmentary glaucoma); previously treated with ocular hypotensive medications; candidate for glaucoma surgery with intraoperative MMC; IOP ≥ 18 mmHg Exclusion criteria: ACG, normal tension glaucoma, or NVG; previous incisional glaucoma surgery, penetrating keratoplasty, extracapsular cataract extraction; visually significant cataract planned for extraction at time of filtering surgery or within 12 months thereafter; any significant ocular disease or history in the operated eye other than glaucoma and cataract; ocular pathology that could interfere with accurate IOP measurements; vitreous present in the anterior chamber for which vitrectomy is anticipated; participation in any other concurrent ophthalmic clinical trial Equivalence of baseline characteristics: yes
Interventions	Intervention 1: trabeculectomy + MMC + Ex‐PRESS (Alco Laboratories, Fort Worth, Texas, USA) Intervention 2: trabeculectomy + MMC Length of follow‐up Planned: 2 years Actual: 2 years
Outcomes	Primary outcomes, as defined: IOP, medication reduction, and surgical success (5 mmHg ≤ IOP ≤ 18 mmHg) Secondary outcomes, as defined: visual acuity, complications, and IOP at 2 weeks' follow‐up Intervals at which outcomes assessed: 1 and 7 days; 1, 3, 6, 12, 18, and 24 months
Notes	Publication type: published article Funding sources: (quote) "research support for this investigator‐initiated trial was obtained from Optonol Ltd. (Neve Ilan, Israel) and Alcon Laboratories, Inc. (Fort Worth, TX)." Disclosures of interest: several co‐authors received research support, consulting fees, and speaker honoraria from industries, but no company wrote or influenced the writing of the manuscript Trial registry: NCT00444080 Study period: not reported Subgroup analyses: none reported Publication language: English Authors contacted for 1‐year IOP and visual acuity data, but no response received.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "Randomization was performed separately for each study site. Each subject was assigned a 3‐digit identifying number, and all subjects were randomized using a computer‐based random‐number generator to undergo treatment with EX‐PRESS glaucoma filtration implant under scleral flap or trabeculectomy."
Allocation concealment (selection bias)	Unclear risk	Not reported.
Masking of participants and personnel (performance bias)	Unclear risk	No‐one was masked in this study. We are uncertain whether this has introduced bias.
Masking of outcome assessment (detection bias)	Unclear risk	The outcome assessors were not masked. However, the authors mentioned that (quote) "we did provide standardized methods for measurement of IOP and documentation of other clinical findings, which may reduce, to some degree, the potential for bias."
Incomplete outcome data (attrition bias) All outcomes	Low risk	The study had 6/120 participants lost to follow‐up and with approximately even numbers of participants lost in the 2 groups.
Selective reporting (reporting bias)	Low risk	The study was registered at www.ClinicalTrials.gov. All defined outcomes in www.ClinicalTrials.gov were reported in full text.
Other bias	High risk	Received funding from manufacturer of device. No other sources of bias identified.