Inclusion Criteria:

1. Diagnosis of primary open angle glaucoma (with or without pseudoexfoliation or pigment dispersion) or ocular hypertension in at least one eye (study eye).
2. Patients who have been on a BAK containing IOP-lowering medication for a minimum of one year with at least the last 6 months on Xalatan® monotherapy and are believed to have OSD.
3. The intraocular pressure in both eyes should be able to be controlled and stable on the study medication alone.
4. Tear Break-up Time (TBUT) of ≤ 6 seconds
5. Must be 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.

Exclusion Criteria:

1. Current use or use within the last 3 months of Restasis®, topical ocular steroids, or topical ocular non-steroidal anti-inflammatory drugs.
2. Current use of punctual plugs.
3. Women of childbearing potential not using reliable means of birth control.
4. Women who are pregnant or lactating.
5. Suspected or diagnosed with Sjogrens's syndrome
6. Current use of any brand of artificial tears containing benzalkonium chloride (BAK).
7. Use of any systemic medications on a chronic basis that have not been 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.
8. Intraocular conventional surgery or laser surgery in study eyes less than six months prior to Visit 1.
9. Current use of contact lenses within 30 days of Visit 1.
10. Presence of other primary or secondary glaucoma not listed in inclusion criterion 1.
11. Any clinically significant, serious, or severe medical or psychiatric condition.
12. A condition, which in the opinion of the Principal Investigator, would interfere with optimal participation in the study, or which would present a special risk to the patient.
13. Participation in any other investigational study within 30 days prior to Visit 1.
14. Known medical history of allergy, sensitivity or poor tolerance to any components of the preparations to be used in this trial that is deemed clinically significant in the opinion of the Principal Investigator.