Evaluation of the Effect of Intravitreal Injections of Anti-VEGF on Macular Perfusion in Diabetic Patients Using OCTA

Anti-vascular endothelial growth factor (VEGF) drugs are the mainstay of therapy for diabetic macular edema (DME), substantially improving visual acuity for many diabetics worldwide, and proving effective for treatment of both non-proliferative and proliferative diabetic retinopathy. Many studies such as Diabetic Retinopathy Clinical Research Network studies, RESTORE Study, and The BOLT Study have supported the use of different anti-VEGF agents in the treatment of DME with better visual outcomes using anti-VEGF injections alone or in combination with other treatments. Several ocular complications of intravitreal anti-VEGF injections have been reported including endophthalmitis, cataract and retinal detachment. The effect of anti-VEGF drugs on macular perfusion has been inconclusive, with mixed reports of increase, decrease or no effect on perfusion in response to anti-VEGF treatment. In many of these studies, however, patients with more ischaemic retinas were not included. Retinal ischemia is an important factor in the progression and prognosis of diabetic retinopathy. Fluorescein angiography (FA) was the method used to assess changes in macular perfusion after anti-VEGF injections in most of the studies. Despite its clinical usefulness, however, FA is known to have documented risks. Optical coherence tomography angiography (OCTA) is a new noninvasive method of acquiring high-resolution images of the retinal vasculature that can be utilized in the treatment of retinal disease without the need for dye injection. It allows the visualization of the superficial and deep retinal capillary layers separately and the construction of microvascular flow maps. Several studies have proved the reliability of OCTA in detecting and quantifying macular ischemia in diabetics. In this study, investigators aim to evaluate the effect of repeated intravitreal injections of different Anti-VEGF agents on the perfusion of different capillary layers in the macula of diabetic patients u