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.