The Glaucoma Laser Trial (GLT): 3. Design and methods. Glaucoma Laser Trial Research Group.

The Glaucoma Laser Trial (GLT) was an investigator-initiated, grant-supported, multicenter, randomized, controlled clinical trial designed to investigate the efficacy and safety of argon laser trabeculoplasty (ALT) as an alternative to medical treatment for newly diagnosed primary open-angle glaucoma (POAG). One eye of each patient was randomly assigned to ALT followed by medical treatment if needed to control intraocular pressure (IOP). The patient's other eye was assigned to medical treatment. Medical treatment for either eye was prescribed according to a stepped sequence. Patients were followed for a minimum of 2 years. Monitoring for control of IOP and for adherence to the protocol continued throughout the followup period. This article describes the design and methods of the trial and provides a discussion of the underlying rationale for key design decisions.