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

Ophthalmology. 2018 May;125(5):774-781. doi: 10.1016/j.ophtha.2017.10.037. Epub 2017 Dec 18.


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.

Publication types

  • Comparative Study
  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alkylating Agents / administration & dosage*
  • Antihypertensive Agents / administration & dosage
  • Glaucoma Drainage Implants*
  • Glaucoma, Open-Angle / physiopathology
  • Glaucoma, Open-Angle / surgery
  • Humans
  • Intraocular Pressure / physiology
  • Mitomycin / administration & dosage*
  • Ophthalmoscopy
  • Postoperative Complications
  • Prosthesis Implantation / methods*
  • Reoperation
  • Tonometry, Ocular
  • Trabeculectomy / methods*
  • Treatment Outcome
  • Visual Acuity / physiology
  • Visual Field Tests
  • Visual Fields / physiology


  • Alkylating Agents
  • Antihypertensive Agents
  • Mitomycin