These include the heart, nerves, blood vessels, kidneys and the eyes. The eyes can be affected in different ways. Diabetes can cause transient blurred vision when a person's blood sugar levels fluctuate wildly. Too high or too low blood sugar levels will change the amount of water in the eye's lens, in turn causing a change in one's vision. Stabilizing the blood sugar will prevent this.
Diabetes also can cause cataracts.
A cataract is a cloudy or opacified lens inside the eye. This cloudiness or opacification leads to blurred vision. As a rule, people with diabetes develop cataracts earlier and faster than people who do not have diabetes. People who have diabetes also have a higher chance of developing glaucoma. Glaucoma is a condition in which the pressure inside the eye is too high.