A 12 Week Comparison of DuoTrav and Xalacom in Open-Angle Glaucoma

Inclusion Criteria: * Patients ≥ 18 years old, diagnosed with primary open angle glaucoma or ocular hypertension * IOP currently uncontrolled on beta blocker monotherapy, as judged by the investigator * Response to Timolol 0.5% was a ≥10% reduction in IOP * IOP at 9:00 of ≥ 20 mmHg while still on beta blocker * Non-prescription and prescription topical ophthalmic products and systemic medications other than those mentioned in the exclusion criteria will be allowed during the study. * Patients wearing contact lenses will be permitted to participate in the study provided that the contact lenses are removed during instillation of study medication and that the patient waits fifteen (15) minutes following drug instillation to re-insert the lenses. Contact lenses cannot be worn on study days. Exclusion Criteria: * Best corrected visual acuity worse than 0.6 logMAR or 20/80 Snellen in either eye. * Patients in whom the mean IOP in either eye at the screening exam visit is greater than 36 mmHg * History of ocular trauma within the past six (6) months. * History of ocular infection or ocular inflammation within the past three (3) months. * History of chronic or recurrent severe inflammatory eye disease (i.e., scleritis, uveitis) * History of severe or serious hypersensitivity to any components of the study medications. * Any abnormality preventing reliable applanation tonometry of either eye. * Intraocular surgery within the past six (6) months as determined by patient history and/or examination. * Patients with cup/disc ratio greater than 0.80 in either eye. * Patients with severe central visual field loss in either eye defined as a sensitivity 10 dB in at least two (2) of the four (4) visual field test points closest to the point of fixation. * History of severe retinal disease such as retinal degeneration, diabetic retinopathy or retinal detachment. * Current use of ANY glucocorticoid administered by any route. Patient must have washed out of the glucocorticoid for at least 4 weeks prior to study entry. * Use of any systemic prostaglandin or prostaglandin analogue (e.g., CYTOTEC) within the last three months. * Current use of topical non-steroidal anti inflammatory agents which inhibit cyclo-oxygenase and prostaglandin analogue synthesis. * Any form of glaucoma other than open-angle glaucoma (with or without a pigment dispersion or pseudoexfoliation component). * Current use of topical non-steroidal anti inflammatory agents which inhibit cyclo-oxygenase and prostaglandin analogue synthesis * Angle grade less than 2 (extreme narrow angle with complete or partial closure) as measured by gonioscopy. * Therapy with another investigational agent within the past 30 days * Patients who would be at risk from treatment with a topical prostaglandin or prostaglandin analogue, are contraindicated for use of beta-blockers or any other medication used in this study, or who would be at risk from participation in the study.