Association of long-term glycaemic control on tear break-up times and dry eye symptoms in Chinese patients with type 2 diabetes.

IMPORTANCE: Diabetes mellitus is known to be associated with dry eye syndrome (DES), but the effects of long-term glycaemic control on tear film metrics and dry eye symptoms are not known in the Chinese population.

BACKGROUND: To evaluate tear film stability and dry eye symptoms and their associations with systemic risk factors in Chinese patients with type 2 diabetes mellitus (T2DM).

DESIGN: Cross-sectional study set at the Lo Fong Siu Po Eye Centre (Grantham Hospital), Hong Kong.

PARTICIPANTS: A total of 80 Chinese participants, aged 18 or above, with T2DM recruited from the specialist outpatient setting were included.

METHODS: The Oculus Keratograph 5M (Oculus Inc., Wetzlar, Germany) was used to measure the non-invasive tear break-up time (NITBUT). Ocular symptoms were evaluated using the Ocular Surface Disease Index (OSDI). The association between OSDI, NITBUT and metabolic parameters relating to diabetes were evaluated using multiple linear regression.

MAIN OUTCOME MEASURES: The associations between long-term glycaemic control and NITBUT and OSDI scores.

RESULTS: Stepwise multiple linear regression analysis revealed glycated haemoglobin to be the only significant independent variable for NITBUT (R2 = 0.099, P = 0.014) and OSDI (R2 = 0.062, P = 0.044) after controlling for potential confounders. The age-adjusted prevalence of DES was 20% (95% confidence interval: 11-30%) in the Chinese T2DM population. The odds of DES for increasing percentage of glycated haemoglobin was 1.49 (95% confidence interval: 1.03-2.17, P = 0.04).

CONCLUSIONS AND RELEVANCE: Our findings highlight the importance of good glycaemic control as a modifiable risk factor for both dry eye symptoms and tear film instability in patients with T2DM.