What Is Diabetic Retinopathy?

A diabetic retinopathy guide

If the person in your care has diabetes, you may already know that the condition can cause vision problems. The most common one is diabetic retinopathy, the leading cause of blindness in working-age Americans. In fact, almost half of Americans with diabetes have some form of diabetic retinopathy. What is it, and how can you help protect someone from its dangers?

The good news about diabetic retinopathy

By keeping blood sugar levels in check, a diabetes patient can help control the progression of the disease.

What happens with diabetic retinopathy?

  • Having diabetes causes blood sugar levels to rise. When these levels remain high for a period of time, tiny blood vessels (capillaries) that nourish the retina can become damaged. This damage, called diabetic retinopathy, is progressive, and it can eventually result in vision loss or blindness.

  • The disease has two main stages: nonproliferative diabetic retinopathy (NPDR) and proliferative diabetic retinopathy (PDR). If someone is in the first stage, it means he has swelling and some bleeding in his eye. When this happens he may have no symptoms or he may have some mild vision loss.

  • In the second, more severe stage -- during which abnormal, fragile blood vessels grow and leak blood into the center of the eye -- his vision may become clouded or even blocked. If he reaches an advanced stage, the abnormal blood vessel growth and scarring can cause glaucoma and detachment of the retina (when scar tissue pulls the retina away from the wall of the eye).

Side effect: macular edema

About half of those people with diabetic retinopathy also develop what's called macular edema, which can cause a noticeable blurring of central vision. It happens when leaking fluid makes the macula swell.

Macular edema can happen at any stage of diabetic retinopathy and whether or not the blood sugar level is elevated -- though it's more likely to show up later in the disease. As the swelling increases or decreases, vision worsens or improves.

Risk factors for diabetic retinopathy

  • Type 1 or type 2 diabetes Almost half of those with diabetes have some degree of diabetic retinopathy. Those who've had diabetes the longest are at highest risk.

  • Other health conditions People with high blood pressure or high blood cholesterol are at higher risk of developing diabetic retinopathy.

  • Pregnancy A woman with diabetes has a higher risk of developing complications, including retinopathy, during her pregnancy.

  • Ethnicity Those of Hispanic or African American heritage are at higher risk of getting the disease.

Diabetic retinopathy: symptoms and treatments

How the world appears to someone with diabetic retinopathy

If a diabetes patient is in any but the late stages of retinopathy, he may have no symptoms at all. That's why eye exams -- at least yearly -- are so important.

And if he has diabetes and experiences symptoms of retinopathy, he should see his eye doctor immediately. According to the National Eye Institute, people with proliferative retinopathy can reduce their risk of blindness by 95 percent with timely treatment and appropriate follow-up care.

Symptoms a diabetes patient may at some point experience include:

  • Blurry vision.
  • Spots, spiders, or cobwebs floating in his field of vision.
  • Dark streaks or a red film blocking his vision.
  • Poor night vision.
  • Trouble adjusting from bright light to soft light.
  • A dark or empty spot in the center of his vision.

To see an image as a patient might see it (and for an explanation of the stages of diabetic retinopathy), visit the National Eye Institute website.

Treatment for diabetic retinopathy

  • If the retinopathy is in an early stage (and the diabetes patient doesn't have macular edema), careful monitoring of his blood sugar levels, blood pressure, and cholesterol may be all that's needed to slow the progression of the disease.

  • If the condition advances, or if he has macular edema, his doctor may recommend laser treatment to control fluid leakage. More than one surgery may be required, and if both eyes need treatment, the surgeries will be scheduled several weeks apart.

  • For proliferative retinopathy, the more serious condition, his doctor will probably suggest laser surgery called pan retinal photocoagulation (PRP). This procedure prevents the growth of more abnormal blood vessels and seals leaking vessels by destroying oxygen-deprived retinal tissue. It will likely take more than one session to complete this laser treatment, too, and afterward the patient may have slightly reduced night and color vision.

  • A vitrectomy, which is a surgical procedure that removes the blood from the center of the eye, may be necessary if the patient's bleeding is severe. To do it, the eye surgeon makes a small incision and removes the blood-clouded vitreous (a gel-like substance in the center of the eye). She'll then replace it with a salt solution.

Researchers are at work developing drugs to stem the growth of abnormal blood vessels in people with proliferative diabetic retinopathy.

Unfortunately, these procedures aren't cures. They may slow or even stop the progression of the disease, but because a patient still has diabetes, he may have further problems with retinopathy down the road.