Travoprost/Timolol vs Latanoprost/Timolol Fixed Combination Therapy

Inclusion Criteria: * Primary open-angle glaucoma or exfoliative glaucoma * Patients who require additional IOP lowering on latanoprost monotherapy * Morning IOP greater than 20 mm Hg on latanoprost monotherapy * Untreated morning IOP greater than 26 mm Hg * Patients older than 29 years * Patients with early to moderate glaucoma (less than 14 decibel (dB) mean deviation visual field loss attributed to glaucoma and 0.8 or better vertical cup-to-disc ratio) * On therapy with latanoprost monotherapy for at least 3 months * Patients with a reliable visual field * Best corrected distance Snellen visual acuity \>1/10 * Corneal pachymetry within the 550 ± 50 μm range * Patients should understand the study instructions * Patients willing to attend all follow-up appointments and willing to comply with study medication usage * Patients who have open, normal appearing angles Exclusion Criteria: * History of combined topical therapy * Contraindication to prostaglandins or timolol * History of ocular trauma or inflammation; intraocular surgery; severe dry eyes; use of contact lenses * Sign of ocular infection except for mild blepharitis * Any corneal abnormality that could have affected the measurement of IOP * Chronic use of topical corticosteroids in the last 3 months before entering the study * Current, or previous use of systemic corticosteroid treatment * Uncontrolled systemic disease * Change of a systemic medication during the study period * Women of childbearing potential or lactating mothers * Inability to understand the instructions and adhere to medications