High glucose levels and high blood pressure can damage the tiny blood vessels in the eye's retina. In time, this damage can cause the blood vessels to swell and weaken. They may become clogged, leak blood into the eye, or may ultimately burst. This condition is called diabetic retinopathy, and it is a leading cause of blindness.

Unfortunately, much of the early damage occurs without any symptoms, which is why it's important to have an eye examination once a year even if your eyesight seems fine to you.

If you have any of these signs of retina damage, see an eye care professional right away:

• Blurry or double vision
• Rings, flashing lights, or blank spots
• Dark or floating spots
• Pain or pressure in one or both eyes
• Trouble seeing things out of the corners of your eyes

Fortunately, diabetic eye disease can be treated if caught early. In the coming weeks, we'll examine the treatment for this and other eye disorders common in diabetes.