National Eye Institute, National Institutes of Health When new, abnormal blood vessels begin to grow on the retina, this is called proliferative retinopathy . When these blood vessels break and bleed into the vitreous, which is the clear, gel-like substance that fills the center of the eye, blood clouds the vitreous and partially blocks light that is passing though the pupil towards the retina. The condition, called vitreous hemorrhage , causes blurred and distorted images. Sometimes the new blood vessels form scar tissue that causes the retina to pull away from the back of the eye. This is called retinal detachment , and can cause severe vision loss if left untreated.
Proliferative retinopathy is the most serious type of diabetic retinal disease.
According to the American Academy of Ophthalmology, it affects up to 20 percent of people with diabetes and can cause severe loss of sight, including blindness. Laser treatment and other types of surgery are effective treatments for diabetic retinopathy, slowing down vision loss in early stages, and reducing the chance of severe vision impairment later on. In laser surgery , a powerful beam of laser light is focused on the retina, and small bursts of light can help seal leaking blood vessels or help bond the retina to the back of the eye, thus preventing retinal detachment. When proliferative diabetic retinopathy is advanced, a vitrectomy may be recommended, removing the vitreous and replacing it with a clear solution. According to the American Academy of Ophthalmology, about 70 percent of people who have had this procedure notice an improvement in sight.