The Primary Tube Versus Trabeculectomy Study: Methodology of a Multicenter Randomized Clinical Trial Comparing Tube Shunt Surgery and Trabeculectomy with Mitomycin C

Abstract

Purpose: To describe the methodology of the Primary Tube Versus Trabeculectomy (PTVT) Study.

Design: Multicenter randomized clinical trial.

Participants: Patients with medically uncontrolled glaucoma and no prior incisional ocular surgery.

Methods: Patients are being enrolled at 16 clinical centers and randomly assigned to treatment with a tube shunt (350-mm² Baerveldt glaucoma implant) or trabeculectomy with mitomycin C (0.4 mg/ml for 2 minutes).

Main outcome measures: The primary outcome measure is the rate of surgical failure, defined as intraocular pressure (IOP) more than 21 mmHg or reduced by less than 20% from baseline, IOP of 5 mmHg or less, reoperation for glaucoma, or loss of light perception vision. Secondary outcome measures include IOP, glaucoma medical therapy, visual acuity, visual fields, and surgical complications.

Conclusions: Practice patterns vary in the surgical management of glaucoma, and opinions differ among surgeons regarding the preferred primary operation for glaucoma. The PTVT Study will provide valuable information comparing the 2 most commonly performed glaucoma surgical procedures.