Diabetic retinopathy is caused by the narrowing of arteries behind the retina. This leads to several complications which are divided into stages. In the first, the damage or narrowing of the artery behind the retina causes the contents of the artery to seep into the eye. Patients in this stage will begin to experience problems with their vision, including blurred vision or darkening of sight. The second stage is even more serious. Here, new blood vessels form behind the eye and since these new vessels are fragile, they burst easily, which causes blood to seep into the eye. When this happens, patients might see black dots, or experience blurred vision—in serious cases, patients are only able to distinguish light from dark. The scary news is, while this blood may take days or months to clear, in some cases, it may take years or never clear at all. Read the rest of the article here.