Blinking and superficial punctate keratopathy in patients with diabetes mellitus

Aim To evaluate blinking patterns in patients with diabetes mellitus and whether blinking contributes to the formation of superficial punctate keratopathy in diabetic patients. Methods We examined 163 patients with type II diabetes mellitus and 76 without diabetes. Blinks were recorded, analysed using six parameters, and compared between patients with and without diabetes. Multivariate regression analysis was performed to assess the influence of other ocular factors, such as status of tear lipid layer, tear breakup time, corneal sensitivity, the result of cotton thread test, or blinking rate related to superficial punctate keratopathy. Results In patients with diabetes, the average mean and maximum interblinking times were longer, the average coefficient of variation of interblinking time was higher, and the average blinking rates were lower than those in patients without diabetes. Multivariate regression analysis revealed that the status of tear lipid layer and tear breakup time were significantly relevant to superficial punctate keratopathy (P<0.01). Conclusion Interblinking time was longer in diabetic patients, resulting in a decreased blinking rate. The prevalence of superficial punctate keratopathy cannot be predicted from blinking patterns in patients with diabetes.