Dry eye disease (DED) is a multifactorial condition of tear production and quality that results in discomfort, visual disturbances, and tear film instability, with potential damage to the ocular surface. Its prevalence ranges from 5% to 30% of the population aged 50 years or more. Numerous clinical and laboratory tests are used alone or in combination to diagnose DED; however, a reference standard test for diagnosis has not been established. While tear osmolarity is a validated indicator of DED, independent of its etiology, the utility of tear osmolarity testing has been hampered by difficulties in tear collection and analytic procedures. Recently a clinically applicable version of the test has been developed.