The Collaborative Initial Glaucoma Treatment Study: study design, methods, and baseline characteristics of enrolled patients.

Objective: The Collaborative Initial Glaucoma Treatment Study (CIGTS) is a randomized, controlled clinical trial designed to determine whether patients with newly diagnosed open-angle glaucoma (primary, pigmentary, or pseudoexfoliative) are better treated by initial treatment with medications or by immediate filtration surgery.

Design: Randomized, controlled clinical trial.

Participants: A total of 607 patients with open-angle glaucoma were enrolled.

Intervention: Patients randomized to initial medications (n=307) received a stepped regimen of medications to lower intraocular pressure. Those randomized to initial surgery (n=300) underwent trabeculectomy to lower intraocular pressure.

Main Outcome Measures: Progression in visual field loss constitutes the study's primary outcome variable. Secondary outcomes include health-related quality of life, visual acuity, and intraocular pressure.

Results: Randomized assignment resulted in a balanced distribution between treatment groups for most demographic and clinical measures assessed at enrollment. More males than females were enrolled (55% were males), and a substantial percentage (38.1 %) of enrollees were blacks. Most enrollees (90.6%) were diagnosed with primary open-angle glaucoma; the remainder had either pseudoexfoliative (4.8%) or pigmentary (4.6%) forms of open-angle glaucoma.

Conclusions: Follow-up of this well-characterized group of patients should provide well-rounded guidance, based on both traditional ophthalmic measures and patients' perspectives on their health-related quality of life, on how best to initially treat open-angle glaucoma.