 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. 