Eye background in case of diabetes. Diabetes can impair the vision. In case of diabetes (mellitus), the body can not adequately make use of sugar. High blood sugar levels damage the vessels of the retina, which impairs the function of the nerve fibers and retinal cells. This damage of retinal vessels is called diabetic retinopathy. The non-proliferating diabetic retinopathy, commonly known as background-retinopathy, is an early stage of diabetic retinopathy. In this stage, blood or liquor seeps out of tiny vessels into the retina, which causes the retina to swell or produce deposits, the so-called hard exsudates. Many patients suffering from diabetes have a mild non-proliferating diabetic retinopathy that normally doesn`t impair their vision. If the vision is impaired, it is due to a macular edema and/or a macular ischemia (lack of supply). A macular edema is a swelling or thickening of the macula, a small area in the center of the retina that enables us to clearly see small details. The swelling is caused by liquor that seeps out of blood vessels into the retina. That is the most common reason for a loss of vision in case of diabetes. The loss of vision can be mild or severe.