By: Christopher E. Starr, MD
Hyperosmolarity is a well-established fundamental characteristic of dry eye disease (DED).1
When patients have dry eye symptoms, osmolarity testing is a logical step to confirm the diagnosis, but what does it mean when the tear osmolarity test is normal in a patient with symptoms suggesting DED?
In the early days of point-of-care tear osmolarity testing, many practitioners faced with this diagnostic dilemma assumed the test was inaccurate because it went against their clinical judgment. When osmolarity testing disagreed, our early reaction was often that the machine must be wrong. We now know otherwise.
Just as tear osmolarity can help us diagnose DED, it can also help us know when to pause and look for an alternative diagnosis. My colleagues and I conducted a study exploring how osmolarity testing can help make alternate diagnoses in symptomatic patients.
Patient symptoms are not an effective method to diagnose dry eye as they often overlap with other pathologies. Tear osmolarity results provide clues for alternative diagnoses.(Ophthalmology Times, March 15, 2017)