Diabetic retinal disease (retinopathy) is the most common cause of blindness in the western world between the ages of 20 and 65. In type 1 diabetes, after 15 to 20 years of disease, retinopathy is present in up to 90% of patients. In type 2 diabetes, retinopathy already exists in one third of the patients when diabetes is diagnosed.
Irrespective of the type of diabetes (type I or II diabetes mellitus) or the type of therapy, high blood sugar levels cause changes in the small blood vessels, which can leak or even become occluded (microangiopathy). This results in insufficient blood flow in the retina. The timing of the onset and progression of this disease can be positively influenced by adequate blood sugar control. In addition, an optimal blood pressure also plays an important role.
In the early stages of diabetic retinopathy, there are usually no symptoms or visual disturbances. Only the ophthalmologist can detect the earliest changes such as vascular dilations (microaneurysms), fatty deposits or small bleedings during an examination of the retina (funduscopy). These early changes usually only need to be observed. However, since this is a sign of a concomitant disease to diabetes, optimal blood sugar and blood pressure control by your treating internist is absolutely necessary. Suboptimal blood sugar control over a longer period of time can lead to serious complications. On the one hand, swelling can develop in the center of vision (macula) (diabetic macular edema), which in the worst case can lead to rapid deterioration in vision, distortions or problems with reading. Another very serious complication is the formation of new blood vessels (proliferative diabetic retinopathy): This arises as a result of lack of oxygen supply to the retina and can exist for a long time without symptoms such as loss of vision or pain. Since these new vessels are very brittle, bleeding into the vitreous body (vitreous hemorrhage) can easily occur. The unrestrained growth of these vessels can also cause retinal detachment, which is the most serious consequence of diabetic retinopathy and leads to blindness if left untreated.
In addition to a detailed medical history and visual acuity check, the examination of the fundus of the eye with a dilated pupil (funduscopy) is the basis of every examination. My recommendation for diabetic patients is an ophthalmological check-up every 6 months – even if they are symptom-free, i.e. without visual disturbances. Optical coherence tomography (OCT) can also be used to precisely depict the center of sharpest vision (macula): With this imaging method, weak laser beams scan the retina and generate high-resolution images of retinal structures. The layers of the retina are displayed with great precision on these cross-sectional images. With the help of this very precise examination, existing fluid deposits in the macula can be detected at a very early stage and possible treatment can be initiated.
Optimum blood sugar and blood pressure control is the most important therapeutic intervention to avoid complications of diabetes, since diabetic retinopathy cannot be cured at the present time. Nevertheless, an improvement or at least a stop of the disease can often be achieved through various treatment options and good control of the diabetes. Special drugs can either inhibit the swelling of the retina or the growth of blood vessels. These are applied directly into the vitreous cavity (IVOM, intravitreal surgical drug application). Timely treatment of the retina with panretinal laser photocoagulation is the therapy of choice. However, this mostly painless treatment has to be repeated in many cases. This can prevent the disease from progressing and prevent severe visual impairment in 50% of cases. If the disease progresses despite laser treatments, vitrectomy (surgical removal of the vitreous body) and retinal surgery are another way of preventing blindness.