Effects of Travatan Z and Xalatan on Ocular Surface Health

Inclusion Criteria: * 18 years of age or older. * Diagnosis of primary open-angle glaucoma (with or without pseudoexfoliation or pigment dispersion) or ocular hypertension in at least one eye (study eye). * Use of BAK (benzalkonium chloride) containing intraocular pressure (IOP) lowering medication for a minimum of one year, including latanoprost (Xalatan®) monotherapy for at least 6 months prior to Visit 1. * IOP controllable and stable on the study medication alone (both eyes). * Believed to have ocular surface disease (OSD). * Tear Break-up Time (TBUT) of ≤ 6 seconds in the study eye. * Willing and able to discontinue the use of any topical ocular medication other than the study medication or BAK free artificial tears for the duration of the study. * Other protocol-defined inclusion criteria may apply. Exclusion Criteria: * Current use or use within the last 3 months of cyclosporine ophthalmic emulsion 0.05% (Restasis®), topical ocular steroids, or topical ocular non-steroidal anti-inflammatory drugs. * Current use of punctual plugs. * Women of childbearing potential not using reliable means of birth control. * Women who are pregnant or lactating. * Suspected or diagnosed with Sjogrens's syndrome. * Current use of any brand of artificial tears containing BAK. * Use of any systemic medications on a chronic basis not on a stable dosing regimen for at least 30 days prior to Visit 1, or an anticipated change in dosing regimen of medications during the course of the study. * Intraocular conventional surgery or laser surgery in study eyes less than six months prior to Visit 1. * Current use of contact lenses within 30 days of Visit 1. * Participation in any other investigational study within 30 days prior to Visit 1. * Other protocol-defined exclusion criteria may apply.