The objective of the study is to see if there is a change in tear osmolarity over time when moderate to severe dry eye subjects are treated with TheraTears® lubricating drops.

The hypothesis is that the measured tear osmolarity from study participants decrease with sustained use of a over-the-counter artificial tears, TheraTears® lubricating drops, over an eight week period. Participant's dry eye symptoms would also improve with sustained use of TheraTears® lubricating drops.

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.