Evaluation of Foveal Avascular Zone and Capillary Plexuses in Diabetic Patients by Optical Coherence Tomography Angiography

PURPOSE: To investigate the foveal avascular zone (AVZ), superficial and deep foveal and parafoveal vessel density (VD) changes related to diabetic retinopathy. METHODS: Forty-nine type 2 diabetes mellitus (DM) and 45 healthy control subjects were included in this study. The demographic data (age and sex), disease duration, and level of glycated hemoglobin were collected. Superficial VD (%), superficial AVZ area (mm²), deep VD (%) and deep AVZ area (mm²) were evaluated via optic coherence tomography angiography. RESULTS: Superficial AVZ was 0.438 ± 0.05 mm² in the DM group, 0.246 ± 0.022 mm² in the control group (p < 0.001). Deep AVZ was 0.732 ± 0.06 mm² in the DM group, and 0.342 ± 0.022 mm² in the control group (p < 0.001). Superficial foveal VD was 29.45 ± 0.76 mm² in the DM group, and 34.86 ± 0.75 mm² in the control group (p < 0.001). Deep foveal VD was 24.85 ± 1.08 mm² in the DM group, and 33.47 ± 0.56 mm² in the control group (p < 0.001). CONCLUSIONS: In this study, we demonstrated an enlargement in the foveal AVZ along with a reduction in the vascular density of the superficial and deep capillary network in the foveal and parafoveal area using optic coherence tomography angiography in patients with nonproliferative diabetic retinopathy. This technique can be used to monitor the progression of the disease and to evaluate the response to treatment.