Pars plana insertion of glaucoma drainage devices for refractory glaucoma

BACKGROUND: Glaucoma drainage devices are more commonly inserted into the anterior chamber because of the relative ease of this method of insertion. However, in certain cases, posterior placement of the tube may be necessary or may be more desirable. The outcome of a series of patients with glaucoma drainage devices inserted into the pars plana was examined. METHODS: Retrospective chart review of patients who underwent pars plana implantation of Molteno and Baerveldt glaucoma drainage devices at the Sydney Eye Hospital. RESULTS: There were 33 cases reviewed. The mean follow-up period was 30.2 months. The mean final postoperative intraocular pressure was reduced to 13.4 +/- 4.4 mmHg (SD) from 33.06 +/- 8.47 mmHg preoperatively. The mean number of intraocular pressure-lowering medications in use postoperatively was 0.6 +/- 0.8, reduced from 3.6 +/- 1.27 medications in use preoperatively. Sixteen (48.5%) eyes were classified as complete successes, 14 (42.4%) eyes as qualified successes and three eyes (9%) as failures. Kaplan-Meier survival analysis for cumulative success (absence of failure) predicted 61.1% survival at 60 months. Complications included five cases of decompensation of corneas or corneal grafts, one case each of conjunctival wound dehiscence, large choroidal effusion, epiretinal membrane, Molteno plate extrusion and intraocular pressure unresponsive to medical therapy, and three cases of tube blockage. CONCLUSIONS: In this series of patients, pars plana insertion of glaucoma drainage devices has been shown to be an effective alternative for selected cases where anterior chamber tube insertion is not possible or is not ideal.