Abstract
Abstract: :
Purpose: Mitomycin C(MMC)application during trabeculectomy is believed to increase the incidence of late postoperative bleb-related infection but this remains unproven. The purpose of this study is to estimate the true incidence of bleb-related infection and to explore the relationship with use of MMC. Methods: Hospital statistics indicated that 3226 trabeculectomies procedures were performed between 1st April 1993 and 31st March 1997. A random sample of 600 (16.4%) of these cases was identified. The case record of each patient was examined for evidence of late post-trabeculectomy blebitis or endophthalmitis. Results: After exclusion of 33 misclassified cases, 491 records of 567 (87%) were examined. Bleb-related infection was diagnosed in 15 eyes (9 blebitis, 2.1%, and 6 endophthalmitis, 1.3%). The cumulative incidence of bleb-related infection was higher in MMC procedures (4.2% blebitis, 3.2% endophthalmitis)(p=0.01, Fischer Exact), than in other trabeculectomies (follow-up 46 ± 1 months)(mean ± SEM). The incidence in MMC cases was 1.0% per year for the first 3 postoperative years, declining to 0.5% per year thereafter. All trabeculectomies were performed at the superior limbus. Conclusion: The cumulative incidence of late bleb-related infection was higher than in previous studies although the annual incidence was similar. A significant excess risk of bleb-related infection was observed with use of MMC.
Keywords: 398 endophthalmitis • 354 clinical (human) or epidemiologic studies: prevalence/incidence