Optical Coherence Tomography-angiography: Comparison of the Foveal Avascular Zone between Diabetic Retinopathy and Normal Subjects

ABSTRACT

PURPOSE: To evaluate the effectiveness of optical coherence tomography angiography (OCTA) in investigating changes in the area of the foveal avascular zone (FAZ) in patients with diabetic retinopathy (DR) and normal subjects. METHODS: Eighty-five eyes of 50 DR patients and 50 eyes of 25 normal subjects were included. OCTA images of the FAZ were acquired using the split-spectrum amplitude decorrelation angiography algorithm of Optovue Avanti RTVue XR OCT. Patients were divided into three groups according to DR severity mild-to-moderate non-proliferative diabetic retinopathy (NPDR) group, severe NPDR group, and proliferative DR group. The area of the FAZ was measured using built-in software and was compared between the patients and normal subjects and among the three groups. RESULTS: The area of the FAZ in patients with diabetic retinopathy (0.46 mm²) was significantly larger than that in normal subjects (0.30 mm², p = 0.001). A significant difference was observed depending on DR severity 0.40 mm² in the mild-to-moderate NPDR group, 0.45 mm² in the severe NPDR group, and 0.53 mm² in the PDR group (p = 0.03). Correlation between area of the foveal avascular zone and visual acuity showed a tendency toward reduction in visual acuity (p = 0.002). CONCLUSIONS: OCTA effectively detected changes in the FAZ area in DR patients. OCTA has the potential to be used for noninvasive quantification and monitoring of the FAZ.