proliferative retinopathy

At this advanced stage, the signals sent by the retina in the third stage trigger the growth of new blood vessels. These new blood vessels are fragile and break easily. They grow along the retina and along the surface of the clear, vitreous gel that fills the inside of the eye. On their own, these blood vessels do not cause symptoms or vision loss. But if they break and leak blood, they can cause severe vision loss and even blindness.