Comparison of Brimonidine Purite, Dorzolamide, and Brinzolamide as Adjunctive Therapy to Prostaglandin Analogs

Inclusion Criteria: * Diagnosis of primary open-angle glaucoma or ocular hypertension. * Must be over 40 years of age. * Intraocular pressure must be 18 mm Hg or higher after 6 weeks of treatment (run-in) with a prostaglandin analog (bimatoprost, latanoprost, or travoprost). Exclusion Criteria: * History of angle closure or narrow angle. * Previous intraocular surgery. * Laser trabeculoplasty within 3 months prior to screening. * History of uveitis or intraocular inflammation. * Use of medications other than the study medications that are known to affect IOP (e.g., beta-blockers, steroids, or angiotensin II blockers) within 3 months of study entry or during the study. * Intolerance of or hypersensitivity to prostaglandin analogs, sulfonamides, alpha-agonists, or the preservative benzalkonium chloride. * Women of childbearing age who are pregnant or not using contraception.