Diabetic retinopathy is a leading cause of blindness and is commonly viewed as a vascular complication of diabetes mellitus. However, diabetes mellitus causes visual dysfunction before the onset of clinically visible microvascular changes associated with diabetic retinopathy. Thus, viewing diabetic retinopathy more generally as a neurovascular disease may lead to an improved understanding of the mechanisms responsible for vision loss. This article reviews the impact of diabetes mellitus on inner and outer retinal visual and electrophysiologic function and advocates for a multimodal approach to the study of diabetic retinopathy.