Summary of findings for the main comparison. Aqueous shunts with versus without mitomycin C for glaucoma.

Aqueous shunts with versus without mitomycin C (MMC) for glaucoma
Population: adults with glaucoma requiring aqueous shunt surgery Settings: ophthalmology clinics Intervention: MMC used during aqueous shunt surgery Comparison: placebo (balanced salt solution)
Outcomes	Illustrative comparative risks* (95% CI)		Relative effect (95% CI)	No of participants (studies)	Certainty of the evidence (GRADE)	Comments
	Assumed risk	Corresponding risk
	Placebo	MMC
Mean IOP (mmHg) Follow‐up: 12 months	Mean IOP ranged from 15.3 to 16.8 mmHg	The effect of MMC on mean IOP compared with no MMC was unclear based on a meta‐analysis of trials (mean difference ‐0.12 mmHg, 95% CI ‐2.16 to 2.41)	‐	78 (3)	⊕⊕⊝⊝ low1,2	Two additional studies reported that mean IOP was lower in the MMC group compared with the placebo group.
Control of IOP, assessed as the mean decrease in IOP from baseline Follow‐up: 12 months	See comment	‐	‐	‐	‐	None of the included studies reported this outcome.
Mean change from baseline in visual acuity Follow‐up: 12 months	See comment	‐	‐	‐	‐	One trial reported lower mean LogMAR values in the MMC group than in the placebo group. Lower LogMAR values represent better visual acuity.
Proportion of participants with stable best‐corrected visual acuity Follow‐up: 12 months	See comment	‐	‐	‐	‐	None of the included studies reported this outcome.
Proportion of participants with decreased visual acuity Follow‐up: 12 months	See comment	‐	‐	‐	‐	Three trials reported that loss of vision was not significantly different between groups (no data available for meta‐analysis).
Proportion of participants with a postoperative hypertensive phase Follow‐up: within 24 hours of surgery	See comment	‐	‐	‐	‐	None of the included studies reported this outcome.
Proportion of participants with an adverse event Follow‐up: 12 months	See comment	‐	‐	85 (2)	⊕⊕⊝⊝ low1, 2	Two studies reported four adverse events (choroidal effusion, corneal edema, flat anterior chamber, and retinal detachment). Due to small numbers of events and sample sizes, no clear difference between MMC and placebo groups was observed.
CI: confidence interval; RR: risk ratio; MMC: mitomycin C; mmHg: millimeter of mercury; IOP: intraocular pressure *The basis for the assumed risk is the mean risk in the placebo group across studies. The corresponding risk (and its 95% CI) is based on the assumed risk in the placebo group and the relative effect of the intervention (and its 95% CI).
GRADE Working Group grades of evidence High certainty: Further research is very unlikely to change our confidence in the estimate of effect. Moderate certainty: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate. Low certainty: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate. Very low certainty: We are very uncertain about the estimate.

¹Downgraded for unclear or high risk of bias among included trials
 ²Downgraded for imprecision (wide confidence intervals)