Risk Factors for Failure in Minimally Invasive Bleb Surgery: A Systematic Review.

PURPOSE

Minimally invasive bleb surgery (MIBS) reduces intraocular pressure (IOP) and IOP-lowering medication use, with a safer adverse effect profile compared to traditional filtration surgery. This review examined risk factors for surgical failure following MIBS.

DESIGN

Systematic review.

METHODS

A systematic review (Prospero

ID

CRD42024572750) of Embase, Web of Science, and MEDLINE identified studies which reported ophthalmic or demographic factors significantly associated with surgical failure following MIBS. Risk of bias was evaluated using Quality in Prognostic Studies (QUIPS), evidence quality using Centre for Evidence-Based Medicine (CEBM), and certainty of evidence using Grading of Recommendations, Assessment, Development and Evaluation (GRADE).

RESULTS

Of 394 articles identified, 18 studies comprising 19 cohorts (9580 eyes of 9281 subjects) were included. Twelve cohorts evaluated the XEN Gel Stent and 7 examined the PreserFlo MicroShunt. Non-White ethnicity (Asian and non-Hispanic Black) and lower intraoperative dosing/omission of intra-operative Mitomycin-C was associated with higher risk of failure; both associations had low certainty of evidence. Associations between glaucoma diagnosis and surgical failure were conflicting, with very low certainty of evidence; several studies described higher risk of failure for pseudoexfoliative/pigmentary, angle closure, uveitic, and normal tension subtypes of glaucoma. Conversely, lower risk of failure was reported among ocular hypertension/open-angle suspects. Most studies had low risk of bias and evidence quality was low to moderate.

CONCLUSION

This review identified demographic and preoperative factors associated with MIBS failure, especially non-White ethnicity and reduced/no MMC use. These findings may guide patient selection and future studies; however, the low certainty of evidence warrants cautious interpretation.