Conjunctival bleb compression as a treatment for hypotony post XEN45 implant in uveitic glaucoma

Purpose: Over-filtration and subsequent hypotony are recognised complications of penetrating glaucoma procedures, especially when augmented with antimetabolites. Patients with uveitis are especially at risk of hypotony and this can reduce the final acuity achieved, compromise surgical outcomes and adversely affect the inflammatory status. The incidence of hypotony following XEN45 implant insertion is higher for uveitic patients and we present a method of surgically addressing this hypotony with transconjunctival compression sutures that are placed over the overdraining XEN45 implant. Methods: We present a retrospective case series of consecutive uveitic glaucoma patients who had conjunctival compression sutures between 2015 and 2018 following XEN45 insertion, at the Manchester Royal Eye Hospital, UK. Two 9/0 nylon sutures were placed in a horizontal figure-of-eight conformation transconjunctivally across the overdraining bleb: one directly over the XEN45 implant and one at the posterior limit of the implant in order to restrict flow. Results: Three patients underwent conjunctival compression sutures following XEN45 implant-related hypotony and all three had successful resolution of their hypotony and visual symptoms. No patients required long-term topical agents to control their intraocular pressure. Conclusion: Conjunctival compression sutures are an effective option for addressing persistent hypotony following XEN45 implant insertion in patients with uveitic glaucoma.

Persistent Hypotony Associated with Immunosuppressive Therapy in Glaucoma Drainage Implant Surgery

Purpose: To describe the histopathology of non-valved implant capsules in three cases of persistent postoperative hypotony after the restrictive tube ligature was released in patients receiving immunosuppressive therapy. Observations: The macroscopic appearance of the capsules 3 and 4 months postoperatively was immature and loose. Microscopic examination disclosed extremely irregular thin tissue, with thicknesses ranging from 0.02 to 0.6 mm, depending on the capsular location studied. Withdrawal of immunosuppressive therapy did not facilitate rebuilding of new capsules. Replacement with a valved implant device was necessary in two cases; the third case recovered with tapering of prednisone. Conclusions and Importance: The use of chronic systemic immunosuppressive therapy might interfere with capsular formation around the plates of drainage devices inducing persistent hypotony. In these cases, the use of valved implants might be safer.