Anterior segment-optical coherence tomography and diabetic retinopathy: Could it be an early biomarker?

Introduction: To measure the corneal thickness (CT), corneal epithelial thickness (CET), and corneal stromal thickness (CST) in patients affected by type 2 diabetes mellitus with good glycemic control and without any signs of diabetic retinopathy using anterior-segment optical coherence tomography (AS-OCT). Methods: 60 eyes of 30 diabetic patients and 60 normal eyes of 30 healthy subjects underwent AS-OCT, evaluation of best-corrected visual acuity (BCVA), intraocular pressure (IOP), slit-lamp biomicroscopy, tear film breakup time (TBUT), Schirmer I test and fundus examination. The CT, CET, and CST maps generated corresponded to a 6-mm diameter area of the cornea that was divided into 17 sectors. We compared the CT, CET, and the CST of each sector obtained in the diabetic group with those obtained in the control group. Results: No significant difference in terms of age, gender, BCVA, IOP, TBUT, and Schirmer I test between the two study groups was observed. The CT, CET, and CST in the central section were significantly thickened in diabetic patients than in controls (p<0.001). Also, each paracentral and midperipheral sector was significantly increased in patients compared to controls (p<0.05). Conclusions: The evaluation of the CT, CET, and CST by AS-OCT could be a valid and non-invasive biomarker in patients effected by diabetes mellitus, useful in early diagnosis of diabetic retinopathy.