Changes in Tear Osmolarity Over Time With Sustained Use of TheraTears

Inclusion Criteria: 1. Is at least 21 years of age and has full legal capacity to volunteer; 2. Has read and signed the information consent letter; 3. Is willing and able to follow instructions and maintain the appointment schedule; 4. Is diagnosed with dry eye syndrome (in at least one eye), indicated by current ocular examination, prior history (self-reported history of dry eye is acceptable) and current use of treatments for dry eye; 5. Has a minimum osmolarity reading of 316 mosm/kg at the baseline visit in at least one eye. Exclusion Criteria: 1. Has taken part in another research study within the last 30 days; 2. Planned contact lens wear during the course of the study; 3. Staff at the investigational site or family member of site staff or family member of currently enrolled participant; 4. Any subject that violates the washout period by using eye drops during the 72hrs washout period; 5. Has any known ocular disease including active ocular infection, inflammation or allergy, especially Salzmann's nodular degeneration, symptomatic conjunctivochalasis, and fixation disparity syndrome; 6. Used Restasis (or similar topical medication) within the last 6 months; 7. Has a systemic condition that in the opinion of the investigator may affect the dry eye status of the subject, especially those newly diagnosed, newly prescribed and/or unstable; 8. Is pregnant, lactating or planning a pregnancy at the time of enrolment (verbal confirmation necessary); 9. Use of medications such as: Systemic Antihistamine (e.g., Allegra®, Benadryl®, Claritin®, Dimetapp®, Unisom®, Zyrtec®, etc.), Isotretinoin (e.g., Accutane®, Roaccutane®, Amnesteem®, Claravis®, Isotroin®, Sotret®) or similar medications; 10. Has known sensitivity to the diagnostic pharmaceuticals to be used in the study; 11. Has undergone ocular surgery(LASIK, Cataract, etc)within the last year.