Retinal nonperfusion drives vision-threatening complications such as pathological neovascularization, which can lead to neovascular glaucoma, vitreous hemorrhage, or tractional retinal detachments and macular edema in various retinal vascular diseases including diabetic retinopathy and retinal vein occlusion. Silva et al revealed that retinal nonperfusion area was correlated highly with diabetic retinopathy severity in their recent paper. It should be clarified that retinal nonperfusion is not synonymous with retinal ischemia, which implies tissue hypoxia, but is a useful surrogate.~Retinal nonperfusion has known to be associated with the production of vascular endothelial factor (VEGF). Recently, Campochiaro et al reported that neutralization of VEGF using ranibizumab improved macular edema and reversed the worsening of retinal nonperfusion in patients with retinal vein occlusion and diabetic macular edema. The precise mechanism for improved perfusion in the VEGF treated eye is uncertain. The authors suggested that VEGF exacerbates retinal ischemia by increasing leukostasis, and intravitreal anti-VEGF agents may break the feedback loop, allowing reperfusion to occur. There might be a portion of circulation that is closed but not permanently, and this reversible closure is modulated by VEGF.~The study by Campochiaro et al, however, was limited in that they reviewed retinal nonperfusion within a template consisting of the Early Treatment Diabetic Retinopathy subfields mainly confined to posterior pole of the fundus. Wide-field retinal imaging is an imaging technique that allows a view of almost 200° of the fundus in a single image. It has been well shown that wide-field scans allow the detection of peripheral pathology that may be missed on 75 degrees of achieved by montaging the Early Treatment Diabetic Retinopathy Study 7-standard fields.~To investigators knowledge, there has been no previous study evaluating the longitudinal change of retinal nonperfusion after aflibercept treatment in a larger area of the retina by taking advantage of the 200° field of view in diabetic retinopathy. The main purpose of this study is to determine the efficacy of intravitreal aflibercept injection in improvement of retinal nonperfusion and identify associated factors in patients with nonproliferative diabetic retinopathy with moderate retinal nonperfusion.
Retinal nonperfusion drives vision-threatening complications such as pathological neovascularization, which can lead to neovascular glaucoma, vitreous hemorrhage, or tractional retinal detachments and macular edema in diabetic retinopathy. Thus, decreasing nonperfusion area with aid of anti-VEGF agents might be a useful way to prevent deteriorating course of diabetic retinopathy. The main purpose of this study is to determine the efficacy of intravitreal aflibercept injection in improvement of retinal nonperfusion and identify associated factors in patients with nonproliferative diabetic retinopathy with moderate retinal nonperfusion.