Diabetes Mellitus

A variable disorder of carbohydrate metabolism caused by a combination of hereditary and environmental factors and usually characterized by an inadequate secretion of insulin by the pancreas or proper utilization of the available insulin, by excessive urine production, by excessive amounts of sugar in the blood and urine, and by thirst, hunger, and loss of weight; type I (juvenile) diabetes mellitus: insulin-dependent diabetes; type II (adult-onset) diabetes mellitus: non-insulin-dependent diabetes; can cause neovascularization (new blood vessel growth) in the retina (retinitis proliferans), resulting in fragile blood vessels which can bleed into the vitreous humor and lead to severe visual impairment or blindness.