Management and Outcomes of Encapsulated Trabeculectomy Blebs Using Post–Operative Pharmacologic Therapy

Abstract

Abstract: : Purpose: To determine the comparative efficacies of medical management with prostaglandins and beta–blockers on lowering intraocular pressure and promoting regression of encapsulated filtering blebs following trabeculectomy in eyes with non–complicated glaucoma. Methods: A retrospective case study included 776 patients who underwent trabeculectomy between January 1, 1996 and June 1, 2003 at the Cullen Eye Institute and Hermann Eye Center, Houston, Texas. Patients were 18 years or older with primary open angle glaucoma without prior history of neovascular or uveitic glaucoma, bleb revision or combined surgical procedures. Presence of bleb encapsulation was defined as documentation of "Tenon’s capsule cyst (TCC)" or "encapsulated bleb (EB)" on two sequential visits in the chart. Variables measured were: time to onset of encapsulation; duration of bleb encapsulation; IOP: before encapsulation, during encapsulation and following resolution; and medications used prior to surgery and during bleb encapsulation. Results: Encapsulation developed in 39 (8%) of 487 eyes and identification of bleb encapsulation occurred at a mean follow–up time of 4.2 ± 2.5 weeks. Mean intraocular pressure (IOP) levels before, during, and after the encapsulated bleb phase were 16.3 ± 7.5, 23 ± 6.7, and 16.9 ± 6.5 mmHg respectively. Encapsulation resolved with medical management in 29 eyes (74.4%), of which 28.2% was Pred Forte taper and multi–drug therapy; and 23.1% was Pred Forte taper alone. Patient age and gender were not significantly related with the occurrence of EB formation. Conclusions:Filtering bleb encapsulation following trabeculectomy responds well to tapering topical corticosteroids alone or in conjunction with IOP lowering agents. The effect of lowering IOP through steroid withdrawal appeared beneficial over maintaining steroid use to prevent inflammation.

Keywords: clinical (human) or epidemiologic studies: outcomes/complications • intraocular pressure • drug toxicity/drug effects