This type of retinopathy develops from background retinopathy. It is form when fragile new blood vessels on the retina rupture. This causes bleeding into the vitreous. Hence, resulting blocked light from the retina.
The ruptured blood vessels in the vitreous evenly form scar tissue which may tighten and pull on the retina. Over time, this tissue will detach itself from the back of the eye and surgery will be required to rectify the problem. Laser surgery is usually the best opinion.