Diurnal Variation of Tear Meniscus and Tear Osmolarity

Inclusion criteria 1. Is at least 18 years old and has full legal capacity to volunteer; 2. Has read and signed the IRB Informed Consent Document; 3. Is willing and able to follow participant instructions; 4. Has clear corneas; 5. Has 20/100 uncorrected visual acuity or better; 6. Is not a hard (or rigid gas permeable) contact lens wearer within the last year; 7. Was a soft contact lens wearer, but stopped wearing at least 1 week ago; 8. Has dry eye according to the study definition of DES (study subjects). Exclusion criteria 1. Has any systemic disease affecting ocular health except for Sjögren's syndrome; 2. Is using any systemic or topical medications that will affect ocular health except for artificial tears; 3. Has an active ocular disease other than DES, meibomian gland disease or Sjögren's syndrome 4. Has any clinically significant lid or conjunctival abnormalities, neovascularization, corneal scars or corneal opacities; 5. Has limbal or bulbar injection or corneal staining that was clinically significant, which are not due to DES; 6. Has worn rigid gas permeable lenses within 1 year; 7. Has had surgery or an eye injury within 6 months.