Intermediate-term outcome of variable dose mitomycin C filtering surgery

Purpose: Trabeculectomy with adjunctive mitomycin C is associated with high success rates in studies with follow-up of less than 1 year. This report evaluates the visual and intraocular pressure (IOP) outcome in eyes after trabeculectomy with adjunctive mitomycin C 1 to 3 years after surgery in a predominantly white group (98.1%). Methods: The records of 157 eyes of 157 consecutive patients, aged 18 or older, who underwent mitomycin C trabeculectomies for uncontrolled glaucoma of various causes were reviewed. All surgeries were performed between April 1991 and June 1993. The concentration of mitomycin C varied from 0.2 to 0.5 mg/ml and was applied for 30 seconds to 5 minutes (only one patient received 0.2 mg/ml). Of the 157 eyes, 110 eyes were at high risk for failure (previous surgeries or inflammatory glaucoma). Thirty-nine eyes had preoperative IOP less than or equal to 21 mmHg. Results: The mean preoperative IOP was 29.4 +/- 10.3 mmHg. This was reduced to 13.0 +/- 7.6 mmHg at 1 year, 11.5 +/- 6.4 mmHg at 2 years, and 13.4 +/- 7.3 mmHg at 3 years. Cumulative survival rate by life-table analysis was 94.2% +/- 1.9% at 1 year, 92.1% +/- 2.4% at 2 years, and 88.7% +/- 4.0% at 3 years, where failure was defined as reoperation for control of IOP. Complications included cataract formation-progression (n = 31), hyphema (n = 26), choroidal detachment (n = 21), hypotony maculopathy (n = 5), and endophthalmitis (n = 2). Vision deteriorated in 29 eyes and improved by 2 or more Snellen visual acuity lines in 29 eyes. Conclusion: The IOP reduction after mitomycin C filtering surgery is sustained in the intermediate-term, 1 to 3 years, follow-up period.