Correlation between HbA1C and CCT in T2DM

An observational cohort study of central corneal thickness (CCT) in type 2 diabetes mellitus (T2DM) patients in hyperglycemic and euglycemic states. Context: To assess the significance of glycemic control in CCT measurement. Aims: The main aim was to assess the change in CCT with the change in glycemic state by following them after 3 months. Settings and Design: This study was carried out in the department of ophthalmology, SMVMCH, Pondicherry. Materials and Methods: This is an observational cohort study carried out at Sri Manakula Vinayagar Medical College and Hospital after obtaining ethics committee clearance. Fifty-six T2DM patients with HbA1C >7 were included in this study with informed consent. Clinical history with complete ophthalmic examination done, CCT was measured using ultrasonic pachymetry (UP) along with blood samples to measure their blood sugars and HbA1C values. They were advised to follow up on the treatment given by the medical department. Patients were reviewed after 3 months to measure the CCT and blood sugar values. Statistical Analysis: Done using STATA software 16.0. Continuous data and categorical data were assessed using paired t -test and Chi-square test, respectively. Normality of data using Shapiro–Wilk normality test. Statistical significance was adopted with P < 0.05. Results: In our study, the initial mean HbA1C was 9.4 ± 1.9 and mean CCT was 552.6 ± 40.6 μm, whereas follow-up mean HbA1C was 7.1 ± 1.2 and mean CCT was 548.5 ± 38 μm which shows statistical significance. Conclusion: Diabetics present with thicker corneas and there is a decrease in thickness once glycemic control has been achieved. Keeping this in mind, we suggest assessment of CCT in all diabetic patients during clinical work-up.