Mitomycin C Dosing and Safety Profiles in PRESERFLO Microshunt Surgery: A Systematic Review and Meta-Analysis

Topic Does MMC concentration or application duration predict IOP reduction, medication burden, or complication rates in adults with open-angle glaucoma undergoing PRESERFLO MicroShunt (PMS) surgery? This systematic review examines whether a clinically meaningful dose-response relationship exists to guide intraoperative MMC dosing. Clinical relevance The PRESERFLO MicroShunt (PMS) is a subconjunctival drainage device offering a minimally invasive approach to glaucoma surgery. Intraoperative mitomycin C (MMC) is crucial for surgical success, yet the optimal dosing regimen remains undefined. This review evaluates the relationship between MMC concentration and postoperative complications following PMS implantation. Secondary analyses explore the impact of MMC parameters on intraocular pressure (IOP) and medication burden reduction. Methods Medline, Embase, Web of Science, and the Cochrane Library were searched from inception to September 2025. Studies reporting PMS outcomes, including specified MMC concentration and complication rates, were included. Risk of bias was assessed using ROBINS-I and RoB 2.0 tools. Data was stratified by MMC concentration (≤0.2 mg/ml vs >0.2 mg/ml). Primary outcomes were safety event frequencies. Secondary outcomes included mean IOP and medication reduction at 12 months. PROSPERO registration ID: CRD42024521551 Results Thirty studies (1,981 eyes) were included. At 12 months, pooled IOP reduction was 9.85 mmHg (95% CI [8.58-11.12]) and pooled medication reduction was 2.51 drops (95% CI [2.31, 2.71]), with high between-study heterogeneity (I² = 88–97%). Hypotony was less common with MMC exposure exceeding 3 minutes (8%; 95% CI [0–18%]) than with shorter durations (21%; 95% CI [10–31%]). Sample-size weighted meta-regression found no significant dose-response relationship between MMC parameters and IOP reduction. A non-significant positive trend was observed between MMC concentration and medication reduction (β = 1.25 drops/mg/ml, p = 0.072; R² = 0.245). Higher MMC concentrations were not associated with increased complication rates. Conclusion Higher MMC concentrations (>0.2 mg/mL) are not associated with increased complication rates and are linked to a reduced need for early secondary procedures. Future prospective studies are warranted to define optimal concentration-duration protocols and to inform personalised antifibrotic strategies in subconjunctival minimally invasive bleb surgery (MIBS).