Evaluation of Tear Film Osmolarity Among Diabetic Patients Using a TearLab Osmometer.

Purpose: The purpose of the present study is to determine the effects of type 2 diabetes mellitus on tear osmolarity using a TearLab Osmolarity system. Moreover, the relationship between tear film osmolarity and ocular surface discomfort in controlled and uncontrolled diabetic patients was assessed.

Materials and methods: This study included 20 male type 2 diabetic patients aged 20 to 70 years (mean ± SD 49±12). A control group (18-43 years; 32.2 ± 6.5 years) consisting of 40 male subjects was also enrolled for comparison. The tear osmolarity was measured using the TearLab Osmolarity System. The ocular surface disease index questionnaire (OSDI) was used to assess ocular discomfort symptoms.

Results: The mean tear osmolarity was 297 ± 8.00 and 296 ± 11 mOsm/L for controlled and uncontrolled diabetic subjects, respectively, while the average osmolarity in the control group was 299 ± 8.00 mOsm/L. No significant differences were detected in tear osmolarity between the control and diabetes groups. The ocular surface disease index questionnaire (OSDI) score was significantly higher in the diabetic patient group. No significant correlation was found between tear osmolarity and OSDI scores.

Conclusion: The ocular discomfort symptoms score in diabetic patients was significantly higher compared to normal eye subjects. Tear osmolarity was not significantly different in diabetic patients. This finding may be explained by a lack of relationship between tear film parameters and diabetic severity; tear film parameters may correlate more with diabetic duration rather than severity. Therefore, studies focused on diabetes duration and tear film parameters are recommended.