The eyes can be affected in several ways by diabetes mellitus. Diabetic retinopathy is one of the leading causes of irreversible blindness in the United States. This retinopathy can occur with either type 1 or type 2 diabetes mellitus and the development depends on the duration of the disease. Most persons with type 1 diabetes and many of those with type-2 diabetes develop some background (non-proliferative) retinopathy. Proliferative retinopathy is more dangerous and is more likely to occur in poorly controlled diabetes.

3.3.1 Pathophysiology: The uptake of glucose by the synthesis of the body is mediated by the Insulin-like growth factor 1 (IGF-1). An insentivity of glucose uptake receptors to insulin and absence of insulin result in increased …show more content…
Proliferative retinopathy is characterized by abnormal new vessel formation (neovascularization), which occurs on the inner (vitreous) surface of the retina and may extend into the vitreous cavity and cause vitreous hemorrhage. Neovascularization is often accompanied by pre retinal fibrous tissue, which, along with the vitreous, can contract, resulting in traction retinal detachment. Neovascularization may also occur in the anterior segment of the eye on the iris. Neo vascular membrane growth in the anterior chamber angle of the eye at the peripheral margin of the iris can also occur and this growth leads to neo vascular glaucoma. Vision loss with proliferative retinopathy may be …show more content…
If new blood vessels are formed it is called proliferative diabetic retinopathy (PDR).The preceding earlier stage is called non-proliferative diabetic retinopathy (NPDR).The first type (PDR) leads to a potentially irreversible visual damage. Hyperglycemia results in damage to retinal capillaries which lead to the formation of micro aneurysms. Disturbance of blood retinal barrier causes marked arterial narrowing. In Non-proliferative diabetic retinopathy (NPDR) initially there is increase in retinal blood flow. In Proliferative diabetic retinopathy (PDR) there is a decrease of blood flow due to a narrowing of arterioles. This forms the background of diabetic retinopathy. Diabetic retinopathy is one of the most frequent causes of blindness. The research on diabetic retinopathy dates back to Ashton in 1963 who opined that a lot of fundamental scientific investigations have to be done to solve the mysteries of diabetic retinopathy.

The retina is considered to be a direct extention of the cerebral cortex. Just like the brain it is also very sensitive to impaired circulation and the consequent ischemia. Changes are confined to the capillaries in the form of endothelial proliferation followed by micro aneurysms and degeneration of arterial branches. Initially, endothelial proliferation and micro aneurysms occur on the venous side of retinal circulation. Degeneration occurs on the arterial side of circulation