To evaluate long-term tonometric outcomes of same-site trabeculectomy revision with mitomycin C (MMC) after failure of an initial trabeculectomy, and to identify risk factors for failure in patients with open-angle glaucoma.

Retrospective cohort study.

One-hundred and seventeen patients (130 eyes) with primary open-angle, pseudoexfoliation, or pigmentary glaucoma, who failed a first trabeculectomy and who were ≥40 years of age at the time of same-site trabeculectomy revision, were included. Three levels of success criteria were defined: (A) intraocular pressure (IOP) ≤18 mm Hg and IOP reduction of 20%; (B) IOP ≤15 mm Hg and IOP reduction of 25%; and (C) IOP ≤12 mm Hg and IOP reduction of 30%. The primary outcome was the qualified Kaplan-Meier success rate (with or without medications) for each criterion. Cox multivariate regression analysis was used to identify risk factors for failure.

The success rates (± standard error) at the first, third, and fifth years of follow-up for criterion A were 69.7% (± 4.1%), 58.2% (± 4.6%), and 51.1% (± 5.0%); for criterion B these were 60.9% (± 4.4%), 47.8% (± 4.7%), and 44.0 (± 4.8%); and for criterion C, 44.6% (± 4.5%), 29.7% (± 4.4%), and 25.8% (± 4.3%). Mean follow-up was 5.2 (± 3.6) years. A time interval between the first and the same-site trabeculectomy revision of <3 years, worse baseline visual acuity, and dyslipidemia were significant risk factors for failure.

Given the long-term tonometric success rates along with significant medication reduction, same-site trabeculectomy revision with MMC should be considered as a viable option to achieve reasonable IOP targets after a first failed trabeculectomy in open-angle glaucoma patients.