INS and diabetic retinopathy: Diabetic retinopathy should be considered within the context of the β-cell centric model of diabetes whereby diabetes and its complications arise from common pathophysiologic factors that damage the β-cell—inflammation/immune regulation, the interplay of genes with environmental processes (epigenetics), and insulin resistance and abnormal metabolic environment (section Diabetes and Its Complications Arise from Common Pathophysiologies) (6, 39, 40).