Diabetes and Eye Health


by Jeanne Faulkner /


Posted on March 20, 2009 at 9:50 AM

Updated Thursday, Oct 22 at 4:28 PM

About the Author

Jeanne Faulkner is a freelance writer and registered nurse in Portland, Ore. Her work appears regularly in Pregnancy and Fit Pregnancy, and she has contributed articles to the Oregonian, Better Homes & Gardens, Shape and other publications.

Our eyes are like the most technologically advanced camera, clicking images and storing them in our memories all day long. The quality of those images, however, is only as good as the camera itself. If the lens (cornea), film (retina) or aperture (iris) doesn't work properly, or something prevents images from reaching the development lab (optic nerve to brain), you won't get much of a picture. Clear vision is a sweet deal that most of us take for granted. But for those with diabetes, the health of the eyes is at risk: Their vision can become cloudy; if untreated, diabetes can lead to blindness.

An Ounce of Prevention Paul Stromberg, MD, an ophthalmologist with Eye Health Northwest in Oregon City, Milwaukie and Happy Valley, Ore., says: "Prevention is our most important message because diabetes can damage blood vessels in the eye. There's less damage if blood sugar, blood pressure and cholesterol are stable. It's easier to repair eye disease early, before it causes too much damage. We tell patients to eat right, exercise and get their eyes examined at least annually so we catch disease before the patient is aware they have it. Once their vision is affected, damage is often severe and treatment more difficult." The good news is that new technologies and medications make diabetes and eye health easier to manage.

What kinds of problems does diabetes cause? The National Diabetes Information Clearinghouse of the National Institute of Health (NDIC-NIH) says diabetes can damage four parts of the eye:

  1. The retina, which is the lining of photoreceptive nerve cells at the back of the eye that senses light. 
  2. The vitreous, which is the jelly-like fluid that fills the back of the eye and maintains its round shape.
  3. The lens, which controls how much light enters the eye and focuses it on the retina.
  4. The optic nerve, which conducts information from the retina to the brain.

The American Diabetes Association (ADA) says diabetics have a significantly higher risk for developing three specific eye conditions: glaucoma, cataracts and retinopathy. Each one poses serious risks to long-term eye health.

Glaucoma develops when pressure builds up and prevents proper drainage of fluid in the eye. The pressure compresses retinal and optic-nerve blood vessels. Vision is gradually lost because the retina and nerve are damaged.

Steven Mansberger, MD, ophthalmologist with Devers Eye Institute in Portland, Ore., says: "Glaucoma is an optic-nerve disease. The cable that takes information from the retina to the brain is like your cable television, and over time, it breaks down. It affects your peripheral vision first. The scary thing is you don't know you have it unless you've lost your peripheral vision. When you have severe glaucoma, it's like looking through a keyhole." Glaucoma is usually treated with eye drops or pills that cause the eye to produce less fluid or help it to drain more effectively.

Cataracts happen when the eye's lens starts clouding and blocking light. Diabetics are 60 percent more likely to develop cataracts, and tend to get them at an earlier age. According to the ADA, if you are diabetic, you should prevent early cataracts by wearing sunglasses regularly. Cataracts are usually treated with lens-replacement surgery, but with diabetics, retinopathy can get worse after the lens is removed, and glaucoma may develop.

Retinopathy is, Stromberg says, "the biggest troublemaker for diabetics. [It is] a generic term for any kind of disease of the retina. With diabetes, we're concerned about two things: swelling and growth of new blood vessels." The NDIC-NIH explains that the tiny blood vessels supplying the retina swell, weaken, become clogged and break. This diminishes blood flow to the retina and, over time, damages vision. As retinopathy worsens, new, weaker blood vessels grow, break, leak blood into the vitreous and prevent light from reaching the retina. Eventually, the retina scars and pulls away from the back of the eye (retinal detachment). People with retinopathy may see dark floating objects, or large dark spaces. Extreme cases can result in blindness.

Stromberg says laser surgery to remove and cauterize damaged or extra blood vessels is a common course of treatment, but if damage is too extreme, more advanced surgeries are needed to treat hemorrhages and remove scar tissue.

The National Eye Institute recommends that diabetics get a comprehensive dilated eye examination at least once a year. According to Mansberger: "Getting the eyes dilated is crucial, especially with diabetes, because problems can be missed with quick tests. For example, if the doctor checks for glaucoma only by using a machine to check your eye pressure, he'll miss glaucoma in at least 50 percent of the cases. He has to look in the back of the eye, at the optic disc."

Stromberg says, "The key to lifelong clear vision for diabetics is preventing trouble before it starts." It's easier to keep your camera in great working order than it is to take it into the shop for repair. So take the initiative and keep those picture-perfect moments clear for a lifetime.