Visual Evoked Potentials in Diabetic Patients and their Relationship with Peripheral Neuropathy – A Case Control Study.

Diabetes mellitus is a systemic disorder characterized by chronic hyperglycaemia and derangements in the metabolism of carbohydrates, lipids and amino acids secondary to absolute or relative deficiency of normal insulin and or insulin resistance and relative or absolute excess of glucagon. Having been recorded as early as 1500 BC in the Abers Papyrus of Egypt, diabetes mellitus is one of the oldest diseases affecting mankind. It is now a widely prevalent global health problem. The global prevalence of diabetes in adult is around 4%. The prevalence is especially high in India, which by 2025 AD, will become the country harbouring the largest number of diabetics. Every cell in our body rely on the metabolism of carbohydrates, aminoacids and lipids for the integrity of its structure and function. The substrates for the intracellular metabolism are taken up from the interstitial fluid and plasma. The concentration of these substrates in these fluids depends to a great extend on the metabolism by insulin sensitive tissues such as hepatocytes, adipocytes, myocytes etc. Thus the insufficiency of insulin action in diabetes mellitus indirectly affects every cell in the body besides directly affecting the metabolism of insulin dependent cells. Diabetes mellitus is a syndrome which has metabolic and vascular components. The metabolic component consists of derangement in the metabolism of carbohydrates, lipids and aminoacids. The vascular component consists of accelerated atherosclerosis, capillary basement membrane thickening, hyperplasia of endothelial cells, occlusion of capillaries, hyperfiltration, microaneurysm formation and neovascularisation. VEP abnormalities are present in diabetic patients in the form of prolongation of P100 latency and decreased P100 amplitude but are not statistically significant. P 100 amplitude is decreased in patients with peripheral neuropathy