Illinois Society for the Prevention of Blindness

Often there are none in the early stages of the disease. Vision may not change until the disease becomes severe. Nor is there any pain.

Blurred vision may occur when the macula - the part of the retina that provides sharp, central vision - swells from the leaking fluid. This condition is called macular edema. If new vessels have grown on the surface of the retina, they can bleed into the eye, blocking vision. But, even in more advanced cases, the disease may progress a long way without symptoms. That is why regular eye examinations for people with diabetes are so important.