Outcomes of Glaucoma Reoperations in the Primary Tube Versus Trabeculectomy Study

Abstract

To describe the incidence and outcomes of reoperations for glaucoma in the Primary Tube VersusTrabeculectomy (PTVT) Study. Cohort study of patients in a multicenter randomized clinical trial. The PTVT Study enrolled 242 patients with medically uncontrolled glaucoma and no previous incisional ocular surgery. Randomization assigned 125 patients to placement of a tube shunt (350-mm2 Baerveldt glaucoma implant) and 117 patients to trabeculectomy with mitomycin C (MMC, 0.4 mg/ml for 2 minutes). Data were analyzed from patients who underwent additional glaucoma surgery. Outcome measures included intraocular pressure (IOP), use of glaucoma medications, visual acuity, surgical complications, and failure (IOP > 21 mmHg or reduced by <20%, IOP ≤ 5 mmHg, additional glaucoma surgery, or loss of light perception vision). Additional glaucoma surgery was performed in 21 patients in the tube group and 12 patients in the trabeculectomy group in the PTVT Study, and the 5-year cumulative reoperation rate for glaucoma was 18.0% in the tube group and 10.4% in the trabeculectomy group (P= 0.15). Follow-up (mean ± standard deviation [SD]) after additional glaucoma surgery was 35.1 ± 17.7 months in the tube group and 30.1 ± 17.6 months in the trabeculectomy group (P= 0.44). At 3 years after glaucoma reoperation, IOP (mean ± SD) was 15.5 ± 4.8 mmHg in the tube group and 16.6 ± 7.3 mmHg in the trabeculectomy group (P= 0.71). The number of glaucoma medications (mean ± SD) after 3 years of follow-up was 2.1 ± 1.7 in the tube group and 1.7 ± 1.0 in the trabeculectomy group (P= 0.58). The cumulative probability of failure at 3 years after a glaucoma reoperation was 37.8% in the tube group and 21.3% in the trabeculectomy group (P= 0.47). No significant difference in the rate of reoperation for glaucoma was observed after tube shunt implantation and trabeculectomy with MMC in the PTVT Study. Similar surgical outcomes were observed after additional glaucoma surgery, irrespective of the initial procedure to which the patient was randomized. Proprietary or commercial disclosure may be found after the references.