Diabetes is the leading cause of preventable blindness in North America. Uncontrolled high blood sugar can result in many changes within the eye, for example it can cause damage to the eye’s small blood vessels causing them to leak. It can also cause swelling in the lens of the eye as well as in the macula, causing the patient’s vision to blur. As a diabetic patient, regular visits to your eye doctor for a dilated eye exam become very important. In fact, if you are diabetic, OHIP covers a yearly comprehensive exam, in order to prevent any of the aforementioned problems.