The pathophysiology of diabetic retinopathy has been a substantial area of research for decades.

Although early investigations focused on clinically manifesting retinal vascular abnormalities, emerging evidence using retinal image analyses, visual function tests, and translational models supports the degeneration of the inner retina early in diabetes, termed diabetic retinal neurodegeneration (DRN), even before it can be seen as diabetic retinopathy (DR) on fundus examination results.

The coordinated structural, glial, and vascular degeneration of the retinal neurovascular unit, accompanied by functional deficits (eg, electroretinogram, dark adaptation, contrast sensitivity, color vision, and microperimetric and perimetric psychophysical abnormalities) as well as peripheral changes on ultrawide-field imaging, have been recently termed diabetic retinal disease to better reflect detectable abnormalities induced by diabetes.