Diabetic Retinopathy
Anyone with diabetes is at risk of developing Diabetic Retinopathy. In its early stages, there may be little or no visual symptoms. Without early detection and treatment, Diabetic Retinopathy can permanently damage the retina. If the condition is not caught early, it may produce symptoms that affect vision. These include mild blurriness in near, or distance vision, floaters and even the sudden loss of vision. If left untreated, it can cause severe vision loss, and even blindness. Eye surgeons cannot reverse the damage caused by Diabetic Retinopathy, but if caught in time, modern treatment options may help slow its progression, and prevent further vision loss. It is critical for patients with diabetes to be examined on a regular basis, even if they have not yet noticed any symptoms. If a patient experiences any significant change in their vision, they should contact their doctor for an immediate appointment, even if they recently had an examination.
Diabetic eye disease refers to a group of eye problems that people with diabetes may face as a complication of diabetes. All can cause severe vision loss or even blindness.
Diabetic eye disease may include:
- Diabetic retinopathy – damage to the blood vessels in the retina.
- Cataract – clouding of the eye’s lens. Cataracts develop at an earlier age in people with diabetes.
- Glaucoma – increase in fluid pressure inside the eye that leads to optic nerve damage and loss of vision. A person with diabetes is nearly twice as likely to get glaucoma as other adults.
Diabetic retinopathy is the most common diabetic eye disease and a leading cause of blindness in American 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. The retina is the light-sensitive tissue at the back of the eye. A healthy retina is necessary for good vision.
If you have diabetic retinopathy, at first you may not notice changes to your vision. But over time, diabetic retinopathy can get worse and cause vision loss. Diabetic retinopathy usually affects both eyes.
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.
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.
If you have diabetes get a comprehensive dilated eye exam at least once a year and remember:
Proliferative retinopathy can develop without symptoms. At this advanced stage, you are at high risk for vision loss.
Macular edema can develop without symptoms at any of the four stages of diabetic retinopathy.
You can develop both proliferative retinopathy and macular edema and still see fine. However, you are at high risk for vision loss.
Your eye care professional can tell if you have macular edema or any stage of diabetic retinopathy. Whether or not you have symptoms, early detection and timely treatment can prevent vision loss.
If you have diabetic retinopathy, you may need an eye exam more often. People with proliferative retinopathy can reduce their risk of blindness by 95 percent with timely treatment and appropriate follow-up care.
The Diabetes Control and Complications Trial (DCCT) showed that better control of blood sugar levels slows the onset and progression of retinopathy. The people with diabetes who kept their blood sugar levels as close to normal as possible also had much less kidney and nerve disease. Better control also reduces the need for sight-saving laser surgery.
Other studies have shown that controlling elevated blood pressure and cholesterol can reduce the risk of vision loss. Controlling these will help your overall health as well as help protect your vision.
Diabetic retinopathy and macular edema are detected during a comprehensive eye exam that includes:
Visual acuity test – This eye chart test measures how well you see at various distances.
Dilated eye exam – Drops are placed in your eyes to widen, or dilate, the pupils. This allows the eye care professional to see more of the inside of your eyes to check for signs of the disease. Your eye care professional uses a special magnifying lens to examine your retina and optic nerve for signs of damage and other eye problems. After the exam, your close-up vision may remain blurred for several hours.
Tonometry – An instrument measures the pressure inside the eye. Numbing drops may be applied to your eye for this test. Your eye care professional 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 eye care professional believes you need treatment for macular edema, he or she may suggest a fluorescein angiogram. In this test, a special dye is injected into your arm. Pictures are taken as the dye passes through the blood vessels in your retina. The test allows your eye care professional to identify any leaking blood vessels and recommend treatment.
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 scatter laser treatment. Scatter laser treatment 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, scatter laser treatment can save the rest of your sight. Scatter laser treatment may slightly reduce your color vision and night vision.
Scatter laser treatment 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, scatter 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.
Macular edema is treated with laser surgery. This procedure is called focal laser treatment. 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 treatment stabilizes vision. In fact, focal laser treatment reduces the risk of vision loss by 50 percent. In a small number of cases, if vision is lost, it can be improved. Contact your eye care professional if you have vision loss.