Dry eye is very common but can be complicated by many factors.
Tear osmolarity measurement is used in the diagnosis of dry eye disease (DED) throughout the peer-reviewed literature.Mean tear osmolarity is approx 295 mOsms/L
Anterior blepharitis and allergic conjunctivitis is often present in symptomatic patients with normal tear osmolarity.
In dry eye disease symptoms correlate poorly with objective signs. Hyperosmolarity above the normal homeostatic range (275 – 307 mOsm/L) is still evidence of DED.
DED is a chronic and progressive disease. Abnormal (or Dry Eye) values can increase to the mild/moderate range (with a mean value of 315 mOsm/L) to the severe range (with a mean value of 335 mOsm/L).
The osmolarity value will be a composite of the combined effects of either aqueous deficiency or evaporative dysfunction