Diabetic retinopathy: Disease of the retina caused by diabetes that involves damage to the tiny blood vessels in the back of the eye. Early disease may not cause symptoms. As the disease progresses, it enters its advanced, or proliferative, stage. Fragile, new blood vessels grow along the retina and in the clear, gel-like vitreous that fills the inside of the eye. Without timely treatment, these new blood vessels can bleed, cloud vision, and destroy the retina. Everyone with type 1 or type 2 diabetes is at risk for diabetic retinopathy. Swelling in the portion of the retina that is most sensitive to light (macular edema) makes it hard for a patient to do things like read and drive. As new blood vessels form at the back of the eye, they can bleed and further blur vision. Large hemorrhages tend to happen more than once, often during sleep. There are no early warning signs. Diagnosis of diabetic retinopathy is made during an eye examination that includes a visual acuity test, pupil dilation, ophthalmoscopy (to look in the back of the eye), and tonometry (to check the pressures). The two treatments for diabetic retinopathy are laser surgery, to stop the edema and hemorrhage, and vitrectomy, to remove blood from the back of the eye. It is strongly recommended that all diabetics have eye examinations at least once (ideally twice) a year.