Objective: To investigate the efficacy and safety of adjunctive mitomycin when used during a primary trabeculectomy within a series of 89 consecutive patients at 1 and 2 years postoperatively.
Design: A cohort study of all patients who underwent primary trabeculectomy, performed by one of us (P.F.P.), between April 1, 1991, and December 31, 1994. Patients received topical mitomycin in conjunction with a corneal safety valve incision. A trabeculectomy was considered "successful" if it resulted in an intraocular pressure (IOP) of 21 mm Hg or lower and a 30% or greater reduction in the IOP at and after 1 year of follow-up, with or without medications and without a reoperation for an elevated IOP. Survival analysis was used to calculate success rates.
Results: The 1- and 2-year success rates were 85.4% and 77.9%, respectively. The mean IOP was reduced from 26.3 to 11.3 mm Hg at 1 year (n=68) and to 11.9 mm Hg at 2 years (n=56), with 60 (88.2%) of 68 patients off medication at 1 year and 47 (83.9%) of 56 patients off medication at 2 years. Trabeculectomy success rates were significantly lower in black compared with nonblack patients (76.2% vs 87.5% at 1 year, P=.03). Trabeculectomy failure occurred throughout the follow-up period. Endophthalmitis occurred in 2 (2.2%) of the patients, and hypotonia requiring revision occurred in 4 (4.5%) of the patients.
Conclusions: Primary trabeculectomy with the use of intraoperative mitomycin lowered the IOP by 30% or more in 78% (at 2 years) to 86% (at 1 year) of the cases and is associated with a marked reduction in the percentage of patients who require glaucoma medication. Success rates must be evaluated in light of such risks as endophthalmitis and hypotony.