Complications of Type 1 Diabetes

Diabetic retinopathy is an important cause of visual impairment in patients with type 1 diabetes.  It affects primarily the blood vessels of the retina.  Early changes include increased vascular permeability, thickening of the basement membrane of the endothelial cells of the vascular wall, and development of microaneurysms.  These changes eventually lead to formation of retinal edema and exudates, initially with mild visual impairment.  At a later stage, termed proliferative retinopathy, there may be formation of new blood vessels in the retina, growth of fibrous tissue, and hemorrhage of the retina and the vitreous body, leading to severe loss of vision.  At this stage distortion or detachment of the retina may occur, causing further deterioration of vision.  Microaneurysms are seen in approximately 80% of type 1 diabetes patients after 10-20 years and proliferative retinopathy may be present in 40-50% after 20 years.  Intensive insulin treatment and optimal blood glucose control slows or halts the progression of retinal changes.  Advanced changes may be treated by laser photocoagulation, but no causal treatment is available.