by Mayo Clinic
Wet macular degeneration is a chronic eye disease that causes vision loss in the center of your field of vision. Wet macular degeneration is marked by swelling caused by leaking blood vessels that affect the macula (MAK-u-luh), which is in the center of the retina — the layer of tissue on the inside back wall of your eyeball.
Wet macular degeneration is one of two types of age-related macular degeneration. The other type — dry macular degeneration — is more common and less severe. Wet macular degeneration almost always begins as dry macular degeneration. It's not clear what causes wet macular degeneration to develop.
Early detection and treatment of wet macular degeneration may help reduce the extent of vision loss and, in some instances, improve vision.
It's not clear what causes wet macular degeneration. The condition almost always develops in people who have had the dry form of macular degeneration. But doctors can't predict which people will go on to develop wet macular degeneration, which is more severe and progresses more rapidly than dry macular degeneration.
Types of wet macular degeneration
Wet macular degeneration can develop in different ways:
- Vision loss caused by abnormal blood vessel growth. The choroidal neovascularization type of wet macular degeneration develops when abnormal new blood vessels grow from the choroid — the layer of blood vessels between the retina and the outer, firm coat of the eye called the sclera — under and into the macular portion of the retina. These abnormal vessels leak fluid or blood between the choroid and macula. The fluid interferes with the retina's function and causes your central vision to blur. In addition, what you see when you look straight ahead becomes wavy or crooked, and blank spots block out part of your field of vision.
- Vision loss caused by fluid buildup in the back of the eye. Another type of wet macular degeneration, called retinal pigment epithelial detachment, occurs when fluid leaks from the choroid and collects between the choroid and a thin cell layer called the retinal pigment epithelium (RPE). Abnormal choroidal blood vessel growth is usually not seen when the RPE is detached. Instead, fluid beneath the RPE causes what looks like a blister or a bump under the macula.
Factors that may increase your risk of macular degeneration include:
- Increasing age. Your risk of macular degeneration increases as you age. Macular degeneration is most common in people over age 60.
- Having a family history of macular degeneration. If someone in your family had macular degeneration, your odds of developing macular degeneration are higher.
- Being white. Macular degeneration is more common in whites than it is in other races, especially after age 75.
- Being female. Women are more likely than men to develop macular degeneration.
- Smoking cigarettes. Smoking cigarettes increases your risk of macular degeneration.
- Being obese. Being severely overweight increases the chance that early or intermediate macular degeneration will progress to the more severe form of the disease.
- Eating few fruits and vegetables. A diet that includes few fruits and vegetables may increase the risk of macular degeneration.
- Having high blood pressure. Diseases that affect the circulatory system, such as high blood pressure, may increase the risk of macular degeneration.
- Having high cholesterol. An elevated cholesterol level in your blood is associated with an increased risk of macular degeneration.
Wet macular degeneration signs and symptoms typically appear and progress rapidly. Signs and symptoms may include:
- Visual distortions, such as straight lines appearing wavy or crooked, a doorway or street sign looking lopsided, or objects appearing smaller or farther away than they really are
- Decreased central vision
- Decreased intensity or brightness of colors
- Well-defined blurry spot or blind spot in your field of vision
- Abrupt onset
- Rapid worsening
- Hallucinations of geometric shapes, animals or people, in cases of advanced macular degeneration
When to see a doctor
See your eye doctor if:
- You notice changes in your central vision
- Your ability to see colors and fine detail becomes impaired
These changes may be the first indication of macular degeneration, particularly if you are older than 50.
Tests and diagnosis By Mayo Clinic staff
Diagnostic tests for wet macular degeneration may include:
- Testing for defects in your central vision. During a complete eye exam, your eye doctor may use a test called the Amsler grid to test for defects in the center of your vision. If you have macular degeneration, when you look at the grid some of the straight lines may seem faded, broken or distorted.
- Examining the back of your eye. Your eye doctor will examine the back of your eye to look for a mottled appearance that's caused by drusen — yellow deposits that form in people with macular degeneration. To examine the back of your eye, your eye doctor will dilate your eyes using eye drops and then use a special magnifying lens.
- Creating images of the blood vessels in your eye (angiogram). During an angiogram of your eye, a colored dye is injected into a vein in your arm. The dye travels to the blood vessels in your eye. A special camera is used to take pictures of your eye. The pictures show the dye highlighting the blood vessels in your eye. Your eye doctor uses the information from the angiogram images to determine whether the back of your eye shows blood vessel or retinal abnormalities that might be associated with wet macular degeneration.
- Optical coherence tomography. This noninvasive imaging test helps identify and display areas of retinal thickening or thinning. Such changes are associated with macular degeneration. It's often used to help monitor the response of the retina to macular degeneration treatments.
Treatments and drugs
Treatment of wet macular degeneration focuses on stopping progression of the disease.
Medications to stop growth of abnormal blood vessels
Medications may help stop growth of new blood vessels by blocking the effects of growth signals the body sends to generate new blood vessels. These drugs are considered the first-line treatment for all stages of wet macular degeneration.
Medications used to treat wet macular degeneration include:
- Bevacizumab (Avastin)
- Ranibizumab (Lucentis)
- Pegaptanib (Macugen)
These medications are injected directly into your eye. You may undergo repeat injections every four weeks to maintain the beneficial effect of the medication. In some instances, you may partially recover vision as the blood vessels shrink and the fluid under the retina absorbs, allowing retinal cells to regain some function.
Using a laser to destroy abnormal blood vessels (photocoagulation)
During laser therapy, your doctor uses a high-energy laser beam to destroy abnormal, leaky blood vessels under the macula. The procedure is used to prevent further damage to the macula and halt continued vision loss for as long as possible.
Laser therapy is used to treat wet macular degeneration in specific situations. It generally isn't an option if you have abnormal blood vessels directly under the center of the macula. Also, the more damaged your macula is, the lower the likelihood of success. Because of these restrictions, only a small percentage of people who have wet macular degeneration are good candidates for laser therapy.
Using light to activate an injected medication (photodynamic therapy)
Photodynamic therapy is used to treat abnormal blood vessels directly under the fovea. The fovea is a part of your eye that lies at the center of your macula and in healthy eyes provides your sharpest vision. Photodynamic therapy uses a laser that's not as hot as the type used in laser therapy.
The light from the laser used in photodynamic therapy activates a drug called verteporfin (Visudyne), which your doctor injects into a vein in your arm. The drug concentrates in the abnormal blood vessels in your eye. When the light is directed into your eye, the drug becomes activated and damages the abnormal blood vessels.
Photodynamic therapy may halt the loss of your vision or at least slow down the rate of vision loss. After the procedure, you'll need to avoid direct sunlight and intensely bright lights for a few days, until the drug wears off.
The following measures may help you avoid macular degeneration:
- Have routine eye exams. Ask your eye doctor how often you should undergo routine eye exams. A dilated eye exam can identify macular degeneration.
- Manage your other diseases. For example, if you have cardiovascular disease or high blood pressure, take your medication and follow your doctor's instructions for controlling the condition.
- Stop smoking. Smokers are more likely to develop macular degeneration than are nonsmokers. Ask your doctor for help to stop smoking.
- Maintain a healthy weight. If you need to lose weight, reduce the number of calories you eat and increase the amount of exercise you get each day. If you have a healthy weight, work to maintain it by exercising most days of the week.
- Choose a diet rich in fruits and vegetables. Choose a healthy diet that's full of a variety of fruits and vegetables. These foods contain antioxidant vitamins that reduce your risk of developing dry macular degeneration.
- Include fish in your diet. Omega-3 fatty acids, which are found in fish, may reduce the risk of dry macular degeneration. Nuts, such as walnuts, also contain omega-3 fatty acids.