Proliferative diabetic retinopathy. These photographs are from the same patient. The right optic nerve has 2 new vessels over the superior aspect of the optic nerve. The left optic nerve has more advanced neovasculizaton. To prevent progression of the neovasculization and possible vitreous hemorrhage, panretinal photocoagulization is required. Early diagnosis and treatment of neovasculization is important to prevent visual disability.