Rosentreter 2010.

Methods	Study design: parallel‐group randomized controlled trial Number randomized: 20 eyes of 20 participants total; 10 eyes of 10 participants in each group Exclusions after randomization: none reported Losses to follow‐up: 1 participant died 8 months after surgery in trabeculectomy + MMC group Unit of analysis: individual (1 eye per participant) Number analyzed: 19 participants total; 10 participants in trabeculectomy + Ologen® group; 9 participants in trabeculectomy + MMC group How were missing data handled?: 1 participant with missing data excluded from analysis Power calculation: a power calculation was originally performed for a group of 40 participants, but power of detection was not reported and the study only recruited 20 participants (required sample size not met)
Participants	Country: Germany Mean age: 62.8 years; not reported by intervention group Gender: 8/20 (40%) men and 12/20 (60%) women; not reported by intervention group Inclusion criteria: “primary or secondary open‐angle glaucoma with uncontrolled IOP while receiving maximal tolerable anti‐glaucomatous therapy" Exclusion criteria: “angle‐closure glaucoma, post‐traumatic, uveitic, neovascular, or dysgenetic glaucoma were not considered for this study. Participants with an allergy to collagen, preliminary conjunctival damage (trauma, vitreo–retinal surgery, previous glaucoma surgery, and other) or those < 18 years of age were excluded from the study.” Equivalence of baseline characteristics: yes
Interventions	Intervention 1: trabeculectomy + Ologen® (Aeon Astron Europe BV, Leiden, The Netherlands) Intervention 2: trabeculectomy + MMC Length of follow‐up: Planned: 12 months Actual: 12 months
Outcomes	Primary outcomes, as defined: IOP, number of glaucoma medication, filtering bleb Secondary outcomes, as defined: visual acuity, visual field, and complications Intervals at which outcomes assessed: 1, 7, and 14 days and 1, 2, 3, 6, and 12 months (except visual field examination only done at 6 and 12 months)
Notes	Publication type: published article Funding sources: “PJ Dahlhausen & Co. GmbH (Emil‐Hoffmann‐Str. 53, 50996 Cologne, Germany) supported the study” Disclosures of interest: “the sponsor had no role in the design or conduct of this research” Trial registry: ClinicalTrials.gov: NCT00538590 Study period: not reported Subgroup analyses: none reported Publication language: English Authors not contacted
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	“We initiated a randomised, prospective trial with two study groups undergoing penetrating anti‐glaucomatous surgery (trabeculectomy)" "Randomisation was performed by an individual not involved in the study according to the Consort Guidelines description.” However, the method of sequence generation is not described and thus adequacy cannot be judged
Allocation concealment (selection bias)	Unclear risk	Allocation concealment was not reported
Masking of participants and personnel (performance bias)	Low risk	Because trabeculectomy is a surgical procedure with informed consent, masking of the participants and personnel becomes impossible. However, given that a strict and standardized surgical protocol was followed and differences in the surgical protocol of the 2 groups were minimized, the risk of performance bias is comparably low for a surgical procedure
Masking of outcome assessment (detection bias)	High risk	It is not possible to mask outcome assessors, as devices can be seen during eye examination
Incomplete outcome data (attrition bias) All outcomes	Low risk	“Twenty (10/10) patients, 12 women and 8 men, began the study, and it was completed by 19 patients. One patient from the MMC group died 8 months after surgery.”
Selective reporting (reporting bias)	Low risk	The study was registered in www.ClinicalTrials.gov. All defined outcomes in www.ClinicalTrials.gov were reported in full text.
Other bias	High risk	Total industry support and other source(s) of potential bias identified. “PJ Dahlhausen & Co. GmbH (Emil‐Hoffmann‐Str. 53, 50996 Cologne, Germany) supported the study.” Although the authors state that “The sponsor had no role in the design or conduct of this research”, the risk of bias from an industry‐funded study is unclear. The authors did not specify how power of detection was affected; “the plan was to include a consecutive series of 40 patients (20 to each group).” “After the first 20 patients, an interim analysis was prearranged.” “After interim analysis, the study was aborted because of the significantly lower IOP and significantly higher complete success rate in the MMC group after 1 year (P = 0.01).”