Optical Coherence Tomography Angiography and in Fluorescein Angiography in Diabetic Retinopathy

Diabetic retinopathy (DR) is the leading cause of decreased vision in working age people. Patients with DR can develop macular edema and proliferative retinopathy which are major causes of visual impairment [1]. The potential of OCTA regarding diagnosis and follow up of DR has been shown in previous studies [2-4]. At present fluorescein angiography (FA) represents the gold standard in the diagnosis and staging of DR [5]. With FA vascular lesions like micro aneurysms (MAs), the size of areas of non-perfusion and of the foveal avascular zone (FAZ) and retinal neovascularisations can be reliably identified [6]. Al-though the capabilities of FA are well known, its use also contains some risks related to the intravenous injection of the dye, which can cause nausea, vomiting and allergic re actions and even anaphylactic shock [7]. Besides that, it also requires time and trained personnel [8]. Image acquisition by OCTA in contrast is not as time consuming and can be performed without taking any risks. Additionally, it provides a 3 dimensional cross sectional view of the retinal and choroidal layers with micro meter depth resolution, providing depth selective information of the retinal vasculature. This facilitates accurate diagnosis and follow up of retinal vascular diseases since significant insights into both morphology and perfusion status can be obtained simultaneously. Although various artifacts appear in OCTA images, a qualitative assessment is mostly possible [9].Early changes to be seen in OCTA in patients with non-proliferative DR are vascular remodelling bordering the FAZ, vascular tortuosity, narrowing of capillary lumen and capillary dilatation. These changes cannot be seen in the same manner in FA [10].In this study we investigated the size of the FAZ and the count of MAs in patients with DR.