Advanced or long-term diabetes can lead to vision-threatening damage to the retina of the eye. Most people have no symptoms at first, but can eventually develop blurred near vision, double vision, floaters, retinal/vitreous hemorrhages and metamorphopsia. In later stages, it can lead to vision loss.
In fact, it is the leading cause of blindness among working-age Americans, according to the U.S. National Institutes of Health (NIH). Yet, many cases could be prevented with regular eye exams and appropriate treatment.