Yes, unfortunately it can. Diabetes is the leading cause of blindness in people between 25 and 74. Diabetic retinopathy is a disease affecting the blood vessels in the retina (the back layer of the eye).
Uncontrolled blood-glucose levels can cause damage to small blood vessels in the eyes, kidneys and nerves.
Damage to larger blood vessels causes poor circulation and can eventually result in a heart attack or stroke.
The combination of nerve damage and poor circulation can place the feet and lower legs at risk of amputation. But the good news is that effective control of your blood-glucose levels can go a long way towards preventing this.