Diabetic Retinopathy

Diabetic retinopathy is one of the leading cause of blindness in adults. It is caused by changes in the blood vessels of the retina. In some people with diabetic retinopathy, blood vessels may swell and leak fluid. In other people, abnormal new blood vessels grow on the surface of the retina.

What are the stages of diabetic retinopathy?

Diabetic retinopathy has four stages:

  • Mild Nonproliferative Retinopathy
  • Moderate Nonproliferative Retinopathy
  • Severe Nonproliferative Retinopathy
  • Proliferative Retinopathy

How does diabetic retinopathy cause vision loss?

Blood vessels damaged from diabetic retinopathy can cause vision loss in two ways:

  • Fragile, abnormal blood vessels can develop and leak blood into the center of the eye, blurring vision. This is proliferative retinopathy and is the fourth and most advanced stage of the disease.
  • Fluid can leak into the center of the macula, the part of the eye where sharp, straight-ahead vision occurs. The fluid makes the macula swell, blurring vision. This condition is called macular edema. It can occur at any stage of diabetic retinopathy, although it is more likely to occur as the disease progresses. About half of the people with proliferative retinopathy also have macular edema.

Who is at risk for diabetic retinopathy?

All people with diabetes--both type 1 and type 2--are at risk. That's why everyone with diabetes should get a comprehensive dilated eye exam at least once a year. The longer someone has diabetes, the more likely he or she will get diabetic retinopathy

Does diabetic retinopathy have any symptoms?

Often there are no symptoms in the early stages of the disease, nor is there any pain. Don't wait for symptoms. Be sure to have a comprehensive dilated eye exam at least once a year.

Blurred vision may occur when the macula—the part of the retina that provides sharp central vision—swells from leaking fluid. This condition is called macular edema.

If new blood vessels grow on the surface of the retina, they can bleed into the eye and block vision.

How are diabetic retinopathy and macular edema detected?

Diabetic retinopathy and macular edema are detected during a comprehensive eye exam that includes:

  • Visual acuity test
  • Dilated eye exam Your doctor checks your retina for early signs of the disease, including:
  • Leaking blood vessels.
  • Retinal swelling (macular edema).
  • Pale, fatty deposits on the retina--signs of leaking blood vessels.
  • Damaged nerve tissue.
  • Any changes to the blood vessels.

If your doctor believes you need treatment for macular edema, he or she may suggest a fluorescein angiogram. The test allows your doctor to identify any leaking blood vessels and recommend treatment.


How is diabetic retinopathy treated?

During the first three stages of diabetic retinopathy, no treatment is needed, unless you have macular edema. To prevent progression of diabetic retinopathy, people with diabetes should control their levels of blood sugar, blood pressure, and blood cholesterol.

Proliferative retinopathy is treated with laser surgery. This procedure is called Pan Retinal Photocoagulation which helps to shrink the abnormal blood vessels. Your doctor places 1,000 to 2,000 laser burns in the areas of the retina away from the macula, causing the abnormal blood vessels to shrink. Because a high number of laser burns are necessary, two or more sessions usually are required to complete treatment. Although you may notice some loss of your side vision, Laser Photocoagulation can save the rest of your sight.

Laser Photocoagulation works better before the fragile, new blood vessels have started to bleed. That is why it is important to have regular, comprehensive dilated eye exams. Even if bleeding has started, laser treatment may still be possible, depending on the amount of bleeding.

If the bleeding is severe, you may need a surgical procedure called a vitrectomy. During a vitrectomy, blood is removed from the center of your eye.


How is a macular edema treated?

Macular edema is treated with laser surgery. This procedure is called focal laser photocoagulation. Your doctor places up to several hundred small laser burns in the areas of retinal leakage surrounding the macula. These burns slow the leakage of fluid and reduce the amount of fluid in the retina. The surgery is usually completed in one session. Further treatment may be needed.

A patient may need focal laser surgery more than once to control the leaking fluid. If you have macular edema in both eyes and require laser surgery, generally only one eye will be treated at a time, usually several weeks apart.

Focal laser photocoagulation stabilizes vision. In fact, it reduces the risk of vision loss by 50 percent.

What happens during laser treatment?

Both focal and Pan Retinal Laser photocoagulation are done. Before the treatment, your doctor will dilate your pupil and apply drops to numb the eye. As you sit facing the laser machine, your doctor will hold a special lens in front of your eye. During the procedure, you may see flashes of light. These flashes eventually may create a stinging sensation that can be uncomfortable. You will need someone to drive you home after surgery. Because your pupil will remain dilated for a few hours, you should bring a pair of sunglasses.

For the rest of the day, your vision will probably be a little blurred. Laser surgery and appropriate follow-up care can reduce the risk of blindness by 90 percent. However, laser surgery often cannot restore vision that has already been lost. That is why finding diabetic retinopathy early is the best way to prevent vision loss.


Fundus photograph of the right eye shows severe non-proliferative diabetic retinopathy with macular edema (a).
Late phase of angiogram shows early microaneurysmal leakage with diffuse late leakage with cystoid changes (b).
Optical coherence tomography line scan shows retinal thickening with spongy retina with cystoid changes in the central area of the retina.