Associations of glycated hemoglobin (HbA1c) level with central corneal and macular thickness in diabetic patients without macular edema

Abstract

Objectives: To determine the correlation between central corneal thickness (CCT) and central macular thickness (CMT), and fasting plasma glucose levels and HbA1c levels before diabetic macular edema (DME) in type 2 diabetes mellitus (DM) patients without diabetic retinopathy. Methods: Forty-four eyes of subjects diagnosed with type 2 DM, and 45 healthy control subjects participated in this study. Detailed ophthalmologic examination was performed with all participants. CMT was measured in both groups by Spectral-domain optical coherence tomography. CCT measurements were made with an Echoscan US-500 ultrasonic pachymeter. Blood biochemical tests for glycated hemoglobin (HbA1c) and fasting plasma glucose levels were run on all patients. Results: The results of the study showed that the mean CCT was significantly thicker in type 2 DM patients 563.84 ± 33.25 μm than in the controls 550.13 ± 28.41 μm (p = 0.039). The mean of CMT was 231.27 ± 37.74 μm in the study group and 225.38 ± 38.33 μm in the control group (p > 0.05). No relationship was found between CCT and CMT and HbA1c level in the study and control groups. Conclusions: The mean CCT was significantly thicker in type 2 DM patients without diabetic retinopathy than in the controls. The mean CMT is thicker in type 2 DM patients without diabetic retinopathy patients than in the controls, but this difference was not statistically significant. Optical coherence tomography can be a perfect detector for early detection of DME.