Stored glycogen, via glucagon, is converted to glucose by a pathway known as glycogenolysis. Gluconeogenesis is the production of glucose in the liver from noncarbohydrate precursors such as glycogenic amino acids. Elevated glucose levels result in the formation of sorbitol (a sugar alcohol) via the aldose reductase pathway. Since sorbitol cannot readily diffuse through cell membranes, cell edema and changes in function can ensue. With respect to the eye, this contributes to the evolution of premature cataractogenesis (nuclear sclerotic, senile and snowflake posterior subscapular cataracts) and sight threatening diabetic retinopathy (compromising the pericytes that line capillary walls). An additional complication of hyperglycemia is nonenzymatic glycosylation. .
There are two types of diabetes, Diabetes type 1 and type 2 diabetes. Type 1 diabetes, which is also called an insulin dependent diabetes mellitus (IDDM), or juvenile onset diabetes mellitus. In type 1 diabetes, the pancreas undergoes an autoimmune attack by the body itself, and is rendered incapable of making insulin. It is in type 1 diabetes where abnormal antibodies are normally found. Antibodies are proteins in the blood that are part of the body's immune system. Patients with type 1 diabetes are insulin dependent for survival. Furthermore in this type there are more 90% of the insulin-producing cells of the pancreas that are destroyed. In this case pancreas produces little or no insulin at all. Most people who develop type 1 diabetes are the age before 30. They are also common among whites (1995, page 12-13). Following are the most common factors that are linked to type 1 diabetes which include: genetics, antibodies, viruses, cow's milk, oxygen free radicals and chemical and drugs. On the other hand, type 2 diabetes people are able to produce insulin but neither people just have not enough insulin or the body does not respond to the action of insulin (1999, pg.
