INS and diabetic retinopathy: Diabetes comprises a group of metabolic diseases that are characterized by chronic hyperglycemia, which is caused by defects in insulin secretion (type 1 diabetes) and/or insulin action (type 2 diabetes), and which may result in lifelong consequences associated with damage to various organs and systems, resulting in complications such as diabetic retinopathy, nephropathy, and neuropathy, and various cardiovascular disorders [1].