Diabetic retinopathy (DR) is the most common complication of diabetes mellitus and has been historically regarded as a retinal microangiopathy. Currently, the diagnosis and classification of DR are still based on vascular abnormalities observed by ophthalmoscopy or color fundus photographs. An increasing number of studies have shown that DR is the result of overall structural and functional disorders of the neurovascular unit, and it is a tissue-specific neurovascular complication. Persistent hyperglycemia in DM not only causes microvascular damage and ischemia, but also leads to retinal inflammation and neuronal degeneration. Furthermore, neurodegeneration often occurs before detectable microvascular lesions. Since 2018, DR has been preferably defined as diabetic retinal disease (DRD), which particularly refers to the effects of diabetes on the entire retina, including neural and vascular components, not only on vascular lesions. The evolution of this term reflects a deepening of the overall understanding of the disease, which helps to promote the improvement of prevention and treatment strategies towards a more systematic and earlier stage. Correspondingly, new challenges have been posed for the assessment, diagnosis, disease staging, and whole disease course management of DRD.
