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Diabetic Retinopathy

What is Diabetic Retinopathy?

Diabetic retinopathy is the leading cause of blindness in the United States. Diabetes damages the body’s normal circulation which is why people with diabetes may have problems with circulation to their legs, kidneys, heart, brain, and eyes. At least 50 percent of all diabetics will develop diabetic retinopathy.

In diabetic retinopathy, high blood sugar levels cause damage to blood vessels in the retina. These blood vessels can swell or leak, or they can close, preventing blood from circulating through them. In some cases, abnormal blood vessels grow on the retina. All of these changes can cause loss of vision.

There are two main types of diabetic retinopathy:

Non-proliferative diabetic retinopathy (NPDR)

This is the early stage, and many diabetics have it. In non-proliferative diabetic retinopathy, there is leakage caused by damage to small retinal blood vessels (capillaries). This leakage allows proteins and lipids from the blood to accumulate in the retina, causing swelling. If this swelling occurs in the area of central vision (macular edema), sight may be significantly diminished. As the disease progresses, retinal capillaries may also become closed off, resulting in poor retinal nutrition. Lack of circulation to the center of vision (macular ischemia) can lead to severe and permanent loss of central vision.

Proliferative diabetic retinopathy (PDR)

This is the more advanced stage. When there is widespread impairment of retinal nutrition due to capillary leakage and closure, proliferative diabetic retinopathy develops. The poorly nourished retina sends out a chemical “distress signal” which causes new blood vessels to grow (proliferate) on the retinal surface. Unfortunately, these new blood vessels are very fragile and often rupture, allowing bleeding to occur within the eye (vitreous hemorrhage). If the bleeding is minimal, you might see a few dark floaters. If they bleed a lot, all vision can be blocked. Scar tissue can also grow around the abnormal blood vessels which may lead to retinal detachment and possible permanent blindness. The proliferative form of diabetic retinopathy is present in approximately 20 percent of patients who have had diabetes for at least 10 years.


In the early stages of diabetic retinopathy, there are usually no symptoms. Therefore, it is very important that all patients with diabetes have a comprehensive dilated eye examination at least once a year before any symptoms develop. During this exam, your eye specialist can check for any signs of damage to the retina and optic nerve, including leaking blood vessels, swelling of the macula, and growth of new vessels. To help prevent the development and progression of diabetic retinopathy, patients are urged to control their blood sugar, blood pressure, and cholesterol levels.

As diabetic retinopathy progresses, symptoms, which usually affect both eyes, may include:

  • Spots or dark strings floating in your vision (floaters)
  • Blurred vision
  • Vision loss
  • Fluctuating vision
  • Impaired color vision
  • Dark or empty areas in your vision

Risk Factors

  • Duration of diabetes — the longer you have diabetes, the greater your risk of developing diabetic retinopathy
  • Poor blood sugar control
  • High blood pressure
  • High cholesterol
  • Pregnancy
  • Tobacco use
  • Being African-American, Hispanic or Native American


It is critical for all diabetics to have a comprehensive eye exam at least once a year to evaluate for the presence of retinopathy. Patients should remember that both macular edema and proliferative retinopathy can develop without symptoms. Patients with visual symptoms and/or visual loss, at any stage of the disease, should be evaluated without delay to find out the cause of the visual change. Early detection and timely treatment can prevent vision loss.

All diabetics should also work to lower their vascular risk factors. Important advice includes:

  • Eat healthy
  • Exercise
  • Avoid smoking
  • Control your blood pressure and blood sugar
  • Lower your cholesterol levels
  • Carefully follow your medical doctor’s instructions


Fortunately, new methods of treatment in recent years have decreased blindness among diabetics and have increased the possibility of retaining useful vision. Your Texas Retina physician will work with you to determine the best treatment plan for your specific situation. You may need multiple procedures or a combination of treatments to control the leaking fluid. Treatment is aimed at the main causes of decreased vision and may include:

Medical Control of Your Diabetes

Anti-VEGF medications, such as Avastin, Lucentis, and Eylea, can help reduce swelling of the macula, slow vision loss and sometimes improve vision. These drugs are given as injections in the eye. Steroid medication, such as triamcinolone, also given by injection to the eye, is sometimes used to reduce macular swelling.


Keeping your blood sugar and blood pressure under control can stop vision loss, and in some cases, good sugar control can even bring some of your vision back.

Laser Surgery

A laser procedure called laser photocoagulation can seal off leaking blood vessels, reduce swelling, and also halt or reverse new vessel growth. Sometimes more than one treatment is needed.


If you suffer from advanced PDR, your Texas Retina physician may recommend a surgical procedure called vitrectomy. In this surgery, vitreous gel and blood from leaking vessels in the back of your eye are removed, helping light rays to focus properly on the retina again. Scar tissue can also be removed, if needed.