Evaluation of early retinal and choroidal microvascular changes in type 2 diabetes patient without retinopathy

Abstract

Purpose: To investigate changes in retinal vascular plexuses and choriocapillaris in patients with type 2 diabetes mellitus (DM) without diabetic retinopathy (DR) using optical coherence tomography angiography (OCTA). Methods: A total of 48 DM and 48 healthy control subjects were included. Mean superficial and deep vessel density (SVD, DVD) and flow in superficial and deep layers, choriocapillaris (CC) and FAZ area were measured by OCTA for analysis. Also, patients were categorized into two groups as high-risk (? 5 years) and low-risk (< 5 years) according to the duration of DM. Results: SVD did not change in eyes without DR, but DVD significantly decreased when compared to healthy controls (p< 0.05). Both superficial and deep layer's flow did not change in diabetic patients who had a significant enlargement in FAZ area. CC flow area and CC thickness did not change in DM patients (p> 0.05). The mean DVD and FAZ area were correlated with HbA1c levels and the duration of DM. Comparison between the high-risk (20 patients) and low-risk groups (28 patients) revealed significant difference in superficial and deep layer's flow, CC and FAZ area (p<0.05). Also, SVD and DVD measurements of the DM patients were significantly different between high-risk and low-risk groups for all macular regions (p<0.05 for all). Conclusions: OCTA can show the damage in patients without any clinically significant DR before the clinical manifestation in diabetic patients. Our results suggested that OCTA might be a promising tool for periodic screening of diabetic patients without DR. © 2020 Gazi Eye Foundation. All rights reserved.