Tear osmolarity and dry eye symptoms in diabetics

Purpose: To assess the relationship between tear osmolarity and dry eye symptoms in patients with diabetes. Patients and methods: Fifty patients with diabetes were enrolled. Demographic information and past medical history were recorded. Symptoms were assessed using the ocular surface disease index (OSDI). Tear osmolarity of each eye was measured with the TearLab (R) Osmolarity System. Results: The majority of the subjects were female (76%), African American (56%), and/or had a diagnosis of type 2 diabetes (82%). The mean +/- standard deviation (SD) for age was 54.6 +/- 13.4, and maximum tear osmolarity was 304.6 +/- 12.7 mOsm/L. Men had higher osmolarity than women (mean +/- standard error (SE) 311.8 +/- 4.0 mOsm/L versus 302.3 +/- 1.9 mOsm/L, P=0.02). Age, race, use of artificial tears, years of diabetes, and hemoglobin A1c did not have a statistically significant association with tear osmolarity. Longer duration of diabetes was associated with lower (less severe) OSDI scores (r=-0.35, P=0.01). Higher tear osmolarity was associated with lower (less severe) OSDI scores (r=-0.29, P=0.04). Conclusion: Approximately half of the diabetic subjects in our study had elevated tear osmolarity, and half of our population also reported symptoms consistent with dry eye disease. However, the two were slightly inversely related in that those with higher osmolarity reported fewer symptoms. Subjects with a longer duration of diabetes also reported fewer dry eye symptoms. Therefore, health care providers should be aware that patients who are most likely to have ocular surface disease, including those with long-standing diabetes, may not experience symptoms and seek care in a timely manner.