One of the first clues for type 2 diabetes may be a small amount of bleeding in the retina, which is a symptom of diabetic retinopathy. “I see patients every day who have this damage and who haven’t yet been diagnosed with diabetes,” says Pizzimenti. Left untreated, the condition can lead to blindness, but managing it cuts this risk in half. When diabetic retinopathy is detected early, lifestyle changes such as eating healthier and losing weight can help prevent further damage. It’s easy for people to miss these silent symptoms of diabetes.
High blood pressure
Blood vessel damage, including weakening and narrowing of the arteries, can signal high blood pressure, says Jessica Ciralsky, MD, assistant professor of ophthalmology at Weill Cornell Medical College in New York City. Multiple large-scale studies have found links between heart disease and narrowing of small blood vessels in the retina, according to a paper in the American Journal of Medicine. These connections are particularly strong in people without traditional heart disease risk factors.
Optic neuritis—inflammation of the optic nerve—can be a harbinger of MS, a degenerative disease of the nervous system, says Mitchell Munson, president of the American Optometric Association. Optic neuritis occurs in 75 percent of patients with MS and is the first symptom of the disease in up to 25 percent of cases. (A diagnosis of optic neuritis doesn’t automatically mean you have MS; it could also be the result of an infection or other causes.) “Patients with optic neuritis often have blurred vision, but I have diagnosed this in some people with no symptoms at all,” Munson says. Watch out for more silent MS symptoms that are easy to overlook.