The 2014 National Diabetes Statistics Report published by the CDC found that 29.1 million people in the United States have diabetes.

In a 2015 study published by the Journal of the American Medical Association, diabetes had yet to be diagnosed in 30 to 50 percent of those with the condition.

Untreated or uncontrolled diabetes can have devastating consequences on the whole body, and the eyes are definitely no exception.

Diabetes is the number one cause of preventable blindness in the Western world, and up to 30 percent of those with diabetes experience some form of visual impairment.

The retina, which lines the back of the eye and contains the photoreceptors necessary for vision, uses nutrients from the blood stream at a higher rate than most other parts of the body.

A network­ of blood vessels supplies these nutrients.

The eye is the only place in the body where blood vessels can be directly viewed, and your eye doctor will do so at your dilated eye exam.

Earliest complications in the eyes from diabetes are small hemorrhages in the retina where blood has leaked out of the vessels and into the surrounding retina. These are painless and do not affect vision.

Fluid can also leak into the macula, which is the part of your retina responsible for your central vision. This does create significantly blurred vision.

Keep in mind that this leakage is likely happening everywhere in the body but can only be visualized in the eye.

As the condition worsens, new blood vessels might begin to grow in the retina due to the retina being starved for nutrients.

These new vessels are not properly structured, and can begin to pull on the retina as they grow. This can lead to a retinal detachment, which is a potentially blinding condition and necessitates surgical repair.

These new blood vessels can also grow in the area of the eye responsible for draining the fluid out of the eye.

If this happens, the fluid builds up, the eye pressure increases, and glaucoma can result. Glaucoma causes loss of vision initially peripherally, but can eventually cause blindness if untreated.

Additionally, diabetes can cause certain types of cataracts, dry eye, and prescription glasses changes.

It is very important for those with diabetes or pre-diabetes to have annual eye exams.

Sometimes the eye doctor might be the one to find the first signs of diabetes before it has even been diagnosed.

Caroline Bundrick, O.D. is an optometrist practicing at Darling Eye Center, with offices in Bluffton and on Hilton Head Island.