Values of optical coherence tomography angiography for diagnosing diabetic retinopathy and evaluating treatment outcomes

Abstract

To compare the consistency between fundus fluorescein angiography (FFA) and optical coherence tomography angiography (OCTA) for the diagnosis of diabetic retinopathy (DR). Ninety-six diabetic patients (185 eyes) treated from January 2019 to December 2019 underwent OCTA and FFA. The image characteristics of fundus lesions were recorded. Sixty-nine patients (137 eyes) who were diagnosed with DR by both examinations and needed to receive panretinal photocoagulation (PRP) were selected. The retinal nerve fiber layer (RNFL) thickness, macular superficial vascular complex (SVC) and deep vascular complex (DVC) blood flow density, 300μm area surrounding foveal avascular zone (FAZ) (FD300) blood flow density and FAZ parameters were compared. The Kappa coefficient of FFA and OCTA for diagnosing DR was 0.537 (P=0.000). FFA and OCTA had substantial consistency for detecting retinal microaneurysms and macular edema (Kappa coefficient=0.643/0.616, P=0.000), perfect consistency for detecting retinal neovascularization and retinal non-perfusion area (Kappa coefficient=0.809/0.832, P=0.000), and moderate consistency for detecting structural changes in the macular ring (Kappa coefficient=0.423, P=0.000). The RNFL thickness in the peripapillary and the superior temporal, temporal inferior, inferior nasal and superior nasal regions rose 1 week after PRP but declined 1 year after treatment (P<0.05). The macular SVC, DVC and FD300 blood flow density declined 1 week after PRP but rose 1 year after treatment (P<0.05). OCTA shows consistency with FFA for diagnosing DR, which remedies the deficiency of FFA. The reduction in fundus lesions after PRP can be quantified by OCTA.