Maheshwari 2012.

Methods	Study design: parallel‐group randomized controlled trial Number randomized: 40 eyes of 40 participants total; 20 eyes of 20 participants in each group Exclusions after randomization: none reported Losses to follow‐up: none reported Unit of analysis: individual (1 eye per participant) Number analyzed: 40 eyes of 40 participants total; 20 eyes of 20 participants in each group How were missing data handled?: no missing data Power calculation: not reported
Participants	Country: India Age: not reported Gender: not reported Inclusion criteria: requiring glaucoma surgery for uncontrolled IOP in POAG Exclusion criteria: ACG, post‐traumatic,uveitic, neovascular, or dysgenetic glaucoma; allergy to collagen, preliminary conjunctival damage (trauma, vitreo–retinal surgery, previous glaucoma surgery, and other); under 18 years of age Equivalence of baseline characteristics: no; at 1 year, a mean IOP of 15.6 mm Hg in the Ologen group was with 43% reduction and a mean IOP of 10.5 mm Hg in the trabeculectomy group was with 50% group; based on this information, the baseline IOP in Ologen group seemed to be about 30% more than the trabeculectomy group
Interventions	Intervention 1: trabeculectomy + Ologen (brand not reported) Intervention 2: trabeculectomy + MMC Length of follow‐up: Planned: not reported Actual: 12 months
Outcomes	Primary and secondary outcomes not distinguished Outcome, as reported: visual acuity, IOP measurement, filtering bleb, and complications Intervals at which outcomes assessed: 1 day and 1 year after the surgery
Notes	Publication type: published article Funding sources: not reported Disclosures of interest: not reported Trial registry: not registered 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	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	Not reported. Although it is not possible to mask outcome assessors, devices can be easily seen during examination of the eye
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	The number of participants with missing or incomplete outcome assessment was not reported
Selective reporting (reporting bias)	Unclear risk	Protocol was not available. Visual acuity and filtering bleb were defined in the Methods section, but the results were not reported
Other bias	Unclear risk	Did not report source of funding or conflict of interest. The baseline IOP seemed not equivalent between the 2 groups. At 1 year, a mean IOP of 15.6 mm Hg in the Ologen group was with 43% reduction and a mean IOP of 10.5 mm Hg in the trabeculectomy group was with 50% group; based on this information, the baseline IOP in the Ologen group seemed to be about 30% more than the trabeculectomy group