Encapsulated blebs following primary standard trabeculectomy: course and treatment.

Abstract

To investigate the incidence and course of encapsulated filtering blebs (EB) following primary standard trabeculectomy in eyes with non-complicated glaucoma. Records of patients who were being followed-up in Ankara Numune Hospital, 1st Eye Clinic Glaucoma Department were analyzed and 183 eyes of 183 consecutive patients who underwent primary trabeculectomy without antimetabolites were enrolled in the study. Encapsulation developed in 14 (7.6%) of 183 eyes and identification of bleb encapsulation occurred at a mean follow-up time of 5.1 +/- 5.0 weeks (median = 4 weeks). Mean intraocular pressure (IOP) levels before, during, and after the encapsulated bleb phase were 14.1 +/- 3.6, 23.4 +/- 6.9, and 14.4 +/- 3.9 mm Hg respectively. All eyes responded to conservative medical treatment consisting of aqueous suppressants without digital massage, and encapsulation resolved after a mean duration of 8.3 +/- 4.6 weeks (median = 8 weeks). Patient age, gender, glaucoma diagnosis, and preoperative IOP levels were not significantly related with the occurrence of EB formation. There was no significant difference in the use of topical beta-blockers and miotics in patients that developed EB versus those who did not; however, EB developed only in eyes with prior beta-blocker therapy and no encapsulation occurred in the 16 eyes that had not received topical beta-blockers. Mean duration of follow-up was 45.3 +/- 30.7 months (12 to 127 months) in the group without encapsulation and 44.6 +/- 22.7 months (18 to 84 months) in the EB group. Overall success rates of trabeculectomies in eyes with and without EB were not significantly different (100% and 91.7%, respectively). Complete surgical success, however, without antiglaucomatous medications at the last visit was significantly lower in eyes with prior encapsulation (35.7% with EB, 63.9% without EB) (P = 0.014). Filtering bleb encapsulation following primary trabeculectomy responds well to conservative medical IOP-lowering therapy in eyes with glaucoma associated with elevated IOP.