Diabetic retinopathy involves the abnormal growth of blood vessels in the retina. Complications can lead to serious vision problems:
Vitreous hemorrhage. The new blood vessels may bleed into the clear, jelly-like substance that fills the center of your eye. If the amount of bleeding is small, you might see only a few dark spots (floaters). In more-severe cases, blood can fill the vitreous cavity and completely block your vision.
Vitreous hemorrhage by itself usually doesn’t cause permanent vision loss. The blood often clears from the eye within a few weeks or months. Unless your retina is damaged, your vision may return to its previous clarity.
Retinal detachment. The abnormal blood vessels associated with diabetic retinopathy stimulate the growth of scar tissue, which can pull the retina away from the back of the eye. This may cause spots floating in your vision, flashes of light or severe vision loss.
Glaucoma. New blood vessels may grow in the front part of your eye and interfere with the normal flow of fluid out of the eye, causing pressure in the eye to build up (glaucoma). This pressure can damage the nerve that carries images from your eye to your brain (optic nerve).
Blindness. Eventually, diabetic retinopathy, glaucoma or both can lead to complete vision loss.