They are white and obscure underlying vessels. Hard exudates are caused by chronic edema. They are yellow and generally deep to retinal vessels. In advanced disease, neovascular membranes can occur, resulting in a traction retinal detachment. Vitreous hemorrhages may result from neovascularization.
Visual symptoms vary, depending on pathologic events.
For example, a sudden severe loss of vision can occur when there is intravitreal hemorrhage. Visual prognosis with proliferative retinopathy is more guarded if associated with severe retinal ischemia, extensive neovascularization, or extensive fibrous tissue formation. Treatment Control of the diabetes and BP is important. Visual symptoms, including blurred vision, sudden loss of vision in one or both eyes, and black spots or flashing lights in the field of vision, are indications for ophthalmologic referral at any time. Panretinal photocoagulation may diminish or eliminate proliferative retinopathy and neovascularization of the iris.