Comparison between Tear Film Osmolar Cocentration and Other Tear Film Function Parameters

Purpose: To evaluate tear film function in patients with diabetes mellitus (DM) using tear film osmolarity (TFO)measurements compared to other tear film function tests. Methods: DM patients without any history of ocular surface disorder but with potential effects on the tear filmwere enrolled in this cross-sectional study. Data including dry eye symptoms, duration of DM, stage of diabeticretinopathy and blood hemoglobin A1c levels were recorded. Tear film break-up time (TBUT) and basic tearsecretion (Schirmer test) were assessed. TFO was determined using the Tearlab Osmolarity System. The outcomemeasures were the difference between the mean values of TBUT, basic tear secretion and TFO in boththe study and control groups. Results: We recruited 51 DM patients and 20 control subjects with a mean age of 51.2 (range, 21 to 70) and48.5 (range, 24 to 70) years, respectively. A total of 27 patients (53%) and 11 controls (55%) reported dry eyesymptoms (p = 0.668). The mean TBUT was 10.2 + 4.8 seconds in the study group versus 10.5 + 2.8 secondsin controls, which was not significantly different (p = 0.747). The mean Schirmer test score was 8.1 + 4.3 mmin the patients versus 10.1 + 3.0 mm in the controls (p = 0.069). The mean TFO was 294.1 + 12.9 mosmol/Lin the patients versus 291.4 + 14.5 mosmol/L in the controls (p = 0.456). It was significantly higher in patientswith poor glycemic control determined by hemoglobin A1c > 8% (p = 0.003). TFO had a positive correlationwith the duration of DM (p = 0.030) but not with the stage of diabetic retinopathy (p = 0.944). However, TFOshowed a significant relationship with dry eye symptoms (p = 0.001). Conclusions: TFO is impaired in patients with uncontrolled DM and is better correlated with glycemic controland dry eye symptoms than the TBUT and Schirmer tests. KCI Citation Count: 0