24-hour Intraocular Pressure Control With Travoprost/Timolol Fixed Combination Versus Travoprost

Inclusion Criteria: * Consecutive adults with primary open-angle glaucoma (POAG) who exhibit a mean untreated IOP greater than 23 m Hg at baseline (10:00). * Patient has POAG and is older than 29 years * The IOP without treatment is greater than 23 mm Hg and lower than 38 mm Hg at baseline (2 readings at 10:00) * Patient can be safely washed out without risk for significant deterioration * Distance best corrected Snellen visual acuity better than 1/10 * Patient can understand the instructions and comply to medications * Open normal appearing angles Exclusion Criteria: * Contraindications to prostaglandins or β-blockers * History of lack of response (\<10% reduction) to any medication * Female of childbearing potential or lactating mother * History of trauma, inflammation, surgery, past use of steroids (within 2 months), severe dry eyes and use of contact lenses * Sign of ocular infection, except blepharitis, corneal abnormality that may affect IOP measurements etc