Proliferative Diabetic Retinopathy 

 As the damage to the capillaries becomes worse, the retina does not get adequate blood flow. Because it is not getting enough blood flow, the eye stimulates the growth of new blood vessels in an attempt to increase the blood flow to the retina. Vascular endothelial growth factor (VEGF) is believed to play a prominent role in this process. 

The new blood vessels that grow are abnormal, however, and do not supply additional blood flow to the retina. The blood vessels grow from the surface of the retina rather than within the retina. The blood vessels can result in the development of multiple vision-threatening problems within the eye. 

 These blood vessels are abnormally leaky and have a great tendency to bleed (hemorrhage) within the eye. It is possible for a person with diabetes to have extensive blood vessel damage and extensive growth of abnormal new blood vessels in the eye before they notice any change in vision. 

Bleeding from the abnormal blood vessels can occur at any time, and can be mild or severe. If the hemorrhage is severe, the vision can be severely affected. 

 The growth of abnormal blood vessels is also associated with the development of fibrous or scar tissue on the retina. This fibrous or scar tissue can pull on the retina and create distortion of the retina or even retinal detachment which can severely affect the vision. 

The natural history of proliferative diabetic retinopathy is that the abnormal blood vessels and scar tissue will grow progressively worse and may eventually completely blind the eye.

Retinal Surgery (Vitrectomy)

Often Vitrectomy surgery and/or treatment with Anti-VEGF injections may be required to stop progressive damage to the retina, and may to help restore lost vision due to bleeding or retinal detachment.