Diabetes can cause damage to the blood vessels in the retina at the back of the eye, resulting in Diabetic Retinopathy (DR) and Diabetic Macular Edema (DME).  Blurred vision usually means you need glasses but you should have your eyes checked no matter what. Not only can blurred vision signal a medical problem with the eye itself (like cataracts or macular degeneration), it can also be a sign of a more serious illness like diabetes.  In fact, an August 2014 study found that 73% of diabetic patients sampled reported blurred vision.

Even without trouble seeing, your ophthalmologist may be able to detect diabetes during an eye exam based on irregularities in your retina. Dr. Gans looks for a condition called diabetic retinopathy, which damages the blood vessels in the eye. “We can see areas of bleeding and swelling in the retina, or abnormal blood vessels developing, which are hallmarks of diabetic damage,” he says. This damage can be observed even before vision is affected. When diabetic retinopathy is detected, laser treatments and medications are used to repair blood vessels. However, surgery may be required if the bleeding is severe enough.