Diabetes mellitus is a heterogeneous metabolic disorder characterized by the presence of hyperglycemia, resulting from impaired insulin secretion, defective insulin action, or a combination of both. Diabetic retinopathy is a common microvascular complication of both type 1 and type 2 diabetes. A widely accepted clinical definition of diabetic peripheral neuropathy (DPN) is 'the presence of symptoms and/or signs of peripheral nerve dysfunction in individuals with diabetes, after excluding other potential causes.