The advanced glaucoma intervention tudy (AGI): 5. encapulated bleb after initial trabeculectomy Original Reearch Article

PURPOE: To compare the incidence of encapulated bleb after trabeculectomy in eye with and without previou argon laer trabeculoplaty and to ae other rik factor for encapulated bleb development. METHOD: After medical treatment failure, eye enrolled in the Advanced Glaucoma Intervention tudy (AGI) were randomly aigned to equence of intervention tarting with either argon laer trabeculoplaty or trabeculectomy. In the preent tudy we compared the clinical coure for 1 year after trabeculectomy in 119 eye with failed argon laer trabeculoplaty with that of 379 eye without previou argon laer trabeculoplaty. Data on bleb encapulation were collected at the time that the encapulation wa diagnoed, and 3 and 6 month later. REULT: Of multiple factor examined in the AGI data for the rik of developing encapulated bleb, only male gender and high chool graduation without further formal education were tatitically ignificant. Encapulation occurred in 18.5% of eye with previou argon laer trabeculoplaty failure and 14.5% of eye without previou argon laer trabeculoplaty (unadjuted relative rik, 1.27; 95% confidence limit = 0.81, 2.00; P = .23). After adjuting for age, gender, educational achievement, precribed ytemic β-blocker, diabete, viual field core, and year ince glaucoma diagnoi, thi difference remain tatitically not ignificant. Four week after trabeculectomy, mean intraocular preure wa 7.5 mm Hg higher in eye with (22.5 mm Hg) than without (15.0 mm Hg) encapulated bleb; at 1 year after trabeculectomy and the reumption of medical therapy when needed, thi exce wa reduced to 1.4 mm Hg. CONCLUION: Thi tudy, a did two previou tudie, found male gender to be a rik factor for bleb encapulation. Four tudie, including the preent tudy, have reported a higher rate of encapulation in eye with previou argon laer trabeculoplaty; in two of the tudie, one of which wa the preent tudy, the rate wa not tatitically ignificantly higher; in the other two tudie the rate wa ignificantly higher. The 4-week potoperative mean intraocular preure wa higher in eye with than without encapulated bleb; with the reumption of medical treatment the two mean converged after 1 year.