Tear Glucose Concentration in Normal and Diabetic Subjects

ABSTRACT

Glucose concentration in tears was measured and comparison was made with the blood glucose level in diabetic and non-diabetic subjects. In normal cases the average glucose value in tears was found to be 18.6mg/100ml, whereas in diabetic patients the mean glucose value in tears was 32.8mg/100ml. These values corresponded approximately 17% of the blood glucose concentration. The changes of tear and blood glucose following the oral administration of glucose were also evaluated in normal and diabetic subjects. In normal cases elevation of tear glucose was noted, reaching its maximum value after 1 hour and returned to the normal level after 2 hours. Tear glucose in diabetics was found to be markedly elevated, lasting longer than in normal cases. In normal subjects, tear glucose concentration fell on injection of insulin and returned to the normal level after 2 hours. In these induced hyperglycemic and hypoglycemic states, glucose concentration in tears revealed parallel with the blood glucose. Clinistix test with tears at different levels of glucose concentrations showed a positive reaction when tear glucose concentration was over 30.5mg/100ml. In these positive cases the blood glucose level was more than 150mg/100ml. It can be suggested that the Clinistix test can be used as a screening method of suspected diabetic patients.