Do you have diabetes? If so, you’re certainly not alone. The American Diabetes Association estimates that 30.3 million Americans have diabetes and another 8.1 million have it but haven’t been diagnosed. Another 84.1 million people in the US have prediabetes, and nine out of ten aren’t aware of it. Still, 1.2 million new cases of diabetes are diagnosed in this country every year.

Maintaining healthy glucose (sugar) levels in your blood is a constant concern if you’ve got diabetes. Consistently high blood glucose can damage many parts of the body, such as the heart, kidneys and blood vessels. That includes the tiny blood vessels in the eyes, which can affect the retina, macula, lens and optic nerve.

When high glucose levels negatively affect the blood vessels in the retina, which is an area of light-sensitive tissue located in the back if the eye, it leads to a condition called diabetic retinopathy. There are two main types of retinopathy, nonproliferative and proliferative.

Nonproliferative retinopathy has several stages. It progresses from mild to moderate to severe. It starts as small areas of balloon-like swelling in the tiny blood vessels. These areas may start leaking fluid into the retina. In the moderate stage, the blood vessels that feed the retina may start swelling and distorting, losing their ability to transport blood.

In severe nonproliferative retinopathy, many blood vessels become blocked, which deprives the retina of its nourishing blood supply. Growth factors are also released during this stage. These factors initiate the development of new blood vessels.

Retinal Detachment

In some people, the severe stage progresses into proliferative retinopathy. With that, new blood vessels start growing, but these vessels are very fragile and weak. They can leak blood, which can block vision. Scar tissue can also be created, which can cause the retina to pull away from the back of the eye, a condition called retinal detachment.

Another consequence of retinopathy is macular edema, which is swelling, or the build-up of fluid, in the macula. The macula is the area of the retina responsible for central vision. It’s the macula the enables you to recognize faces, read and drive. Macular edema is the most common cause of vision loss in people who have diabetic retinopathy.

Cataract

If you maintain good control of your blood glucose levels and your blood pressure, you’ll be less likely to develop diabetic retinopathy or, if you do, you’ll get a milder form of it. Those are risk factors you can control. Risk factors you can’t control are your genes and how long you’ve had diabetes.

Having diabetes puts you at higher risk for other eye conditions as well, including cataracts and glaucoma. Rapidly changing blood glucose levels can affect the eye’s lens and cause it to become cloudy. This can lead to a cataract. Anyone can get cataracts, but people with diabetes tend to get them earlier, and they progress faster.

Trabecular Meshwork

With glaucoma, pressure builds up inside the eye when fluid can’t be removed through the eye’s drainage system that includes the trabecular meshwork. High blood glucose levels damage the cells of this meshwork, so it can’t function properly. Fluid doesn’t drain and pressure builds up in the eye. If not treated, the pressure can damage the optic nerve, leading to permanent vision loss.

Diabetic retinopathy, macular edema and glaucoma usually have no early symptoms. You may not know you have these diseases until they’ve already done damage to your eyes and affected your vision. That’s why an annual examination by an eye specialist is so important. The specialist can check your eyes for signs of these disorders, so early treatment can be started.

According to the US Centers for Disease Control and Prevention, about 90 percent of diabetes-related vision loss can be prevented. Early detection is one of the ways to reach that goal, and it’s another reason for an annual eye exam. Another way to help prevent vision-stealing eye diseases is by maintaining good blood glucose and blood pressure control.

Following these simple tips can help save your vision. So can knowing these symptoms  that signal an emergency. If you notice any of these symptoms, call your doctor right away:

• Black spots in your vision
• Flashes of light
• “Holes” in your vision
• Blurred vision