Diabetic retinopathy(DR)has long been recognized as a microvasculopathy, but diabetic retinal neuropathy(DRN), characterized with inner retinal neuroinflammation and neurodegeneration, also occurs in diabetes mellitus(DM), and even precedes the clinically observed vascular changes in DM. Clinical studies have confirmed the diabetic retinal damage as a highly tissue-specific neurovascular complication, and proposed “diabetic retinal disease”(DRD)as the redefined term for DR. DRN is structurally observed as neuronal apoptosis, ganglion cell loss, reactive glial proliferation, and thinning of the inner retina. Functionally, it is manifested as deficits in retinal electroretinogram, adaptation, contrast sensitivity, color vision, and psychophysical tests of microfield and visual field. In-depth studies from an integrated perspective on DRN will have significant impacts on new stages, novel therapy, and management throughout the entire course of DRD.