Optical coherence Tomography Angiography versus fundus fluorescein angiography in assessment of clinically undetected neovascularization in severe non-proliferative diabetic retinopathy patients

Abstract

Diabetic retinopathy is one of the most important challenges that faces the diabetic patients, simply it is a microangiopathy of the retina which leads to impairment of visual abilities if neglected, consists of many factors such as vascular walls changes and alterations in blood physiological criteria. These factors leads to capillary occlusion and so to fluid leakage and retinal ischemia.(1) According to the ETDRS, It is divided into Non-proliferative (mild-moderate-severe) and proliferative retinopathy according to the severity of changes occurs within the retina and the degree of ischemia and new vessels proliferations.(1) To compensate the ischemia resulting from micro-capillary occlusions and hypoperfusion that invade a large portion of the retinal tissue, vascular endothelial growth factor (VEGF) and other mediators take the upper hand and accelerate the new vessels formation process and this leads to proliferative diabetic retinopathy (PDR). Consequences of neglected PDR aren’t favourable, usually show vitreous haemorrhage, tractional retinal detachment and neovascular glaucoma. (1) FFA is considered the gold standard clinical imaging modality for evaluating retinal and choroidal vascular pathologies that based on the optical principle of fluorescence by injection of dye and exciting it with cobalt blue light.(6, 4)