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Macular degeneration, also called age-related macular degeneration, or AMD, is an eye disease that affects people’s central vision. AMD damages the macula, the part of the eye responsible for seeing sharp details at the center of the field of vision.
AMD is a common eye health problem and is the leading cause of permanent close-up (reading) vision impairment in people 65 and older.
There are two forms: dry AMD and the more advanced wet AMD. People with AMD often report that their vision is distorted or blurred. They may not clearly see objects directly in front of them, which interferes with driving, recognizing faces, and watching television. Eventually, they may develop a blind spot or severe distortion in the middle of their field of vision that increases in size as the disease progresses. However, AMD rarely, if ever, causes complete blindness.
The causes of AMD are not well understood. Age is the most critical risk factor. Cigarette smoking, high cholesterol levels, and high blood pressure may also increase your risk. Caucasians are most susceptible to AMD, followed by Asians and Hispanics. Women develop the disease more often than men.
What is the difference between wet and dry macular degeneration?
There are two types of age-related macular degeneration (AMD): dry AMD and wet AMD. Dry is the early form of the disease, and wet is the advanced.
Dry AMD. In dry AMD, the cells of the macula slowly break down. This produces blurring and then blind spots in the eye's central vision. The symptoms are subtle at first, then become more noticeable over time.
Dry AMD has three stages—early, intermediate, and advanced. In the early stage, central vision is usually unaffected, though some minor abnormalities may occur. In the intermediate phase, distortion and blurring appear. The advanced form of dry AMD, also called geographic atrophy, often results in severe vision loss, especially as the center of the macula becomes involved. The blurring becomes more pronounced, making reading or recognizing faces difficult.
Dry AMD can emerge in only one eye at first, though it is likely that the second eye is also affected without showing symptoms. The disease may continue to develop in the second eye, causing symptoms over time. Dry AMD always precedes wet AMD.
Wet AMD. Wet AMD is the disease's advanced, rapidly progressive form and is most likely to cause severe vision loss. Everyone with wet AMD starts out with the dry form. However, only about 10% to 15% of those with dry AMD will go on to develop the wet form.
Wet AMD develops when abnormal blood vessels form in the layer of cells beneath the retina or within the retina. These vessels leak blood and fluid into the macula, causing scarring and significant vision loss, often involving the center of the macula. Wet AMD can cause rapid vision loss over days to weeks and continue over time.
What are the symptoms of macular degeneration?
Age-related macular degeneration (AMD) does not always result in early symptoms. People with dry AMD (the early phase of the disease) will have blurred vision and difficulty seeing images as the disease progresses.
With dry AMD, typically, a blind spot forms in the center of vision. Over time, this area may enlarge, further impairing sight, making images like faces and printed words harder to recognize. Another early symptom is diminished night vision, where you have trouble seeing at night or in dim light.
Distorted vision is a sign of intermediate or advanced dry AMD, and most stages of wet AMD . This happens when leaking blood vessels change the normal position of the macula and cause straight lines to suddenly appear wavy and shapes to look deformed. Colors may seem faded.
While AMD can severely damage central vision, it does not affect peripheral vision, and most people do not go completely blind from even the most severe forms of the disease.
How is dry macular degeneration monitored and treated?
A good way to check for age-related macular degeneration (AMD) is with the Amsler grid test, which you can do at home.
You focus your eyes on a central dot on a grid that resembles graph paper. If the lines near the dot appear wavy or are missing, you may have AMD. (You can simulate this test by looking at windowpanes, floor tiles, or ceiling tiles to see if the straight edges look wavy.)
If you already have dry AMD, performing this test regularly can catch signs of progression to advanced wet AMD. Any distortion on the grid may be a sign of wet AMD and should be evaluated.
Unfortunately, there is no cure for AMD. Following a diet that is high in antioxidants and contains lots of leafy green vegetables, such as spinach, collard greens, and kale, may help slow the worsening of dry AMD. For people with intermediate dry AMD, The National Eye Institute's Age-Related Eye Disease Study (AREDS) found that the following daily supplement formula also may slow the disease's progression.
- vitamin C: 500 milligrams (mg)
- vitamin E: 400 international units (IU)
- zinc: 25 mg
- copper (cupric oxide): 2 mg
- lutein: 10 mg
- zeaxanthin: 2 mg
- omega-3 fatty acids (DHA and EPA): 1,000 mg.
Talk with your doctor about whether this vitamin regimen is right for you.
Gene and stem cell therapy are also at the forefront of AMD treatment research. Although both are highly preliminary, they could one day provide long-term disease control with only one treatment.
The FDA also recently approved an eye injection drug called pegcetacoplan (Syfovre) to slow the progression of the advanced form of dry AMD called geographic atrophy. However, it is not approved for other types of dry AMD.
How is wet macular degeneration treated?
Treatment for wet age-related macular degeneration (AMD) centers on a class of medications known as anti-VEGF drugs.
When injected into the eye, these drugs may stop the growth of new abnormal blood vessels. They also decrease leakage from those vessels. Anti-VEGF therapy may even restore lost vision. Patients must get injections regularly for several months to a year, and maybe longer. Anti-VEGF treatments are generally painless. The doctor numbs the eye before administering the injection.
Laser treatment is another possible (though uncommon) option for wet AMD. In general, lasers are used only when the leaking blood vessels are relatively small and located far from the central portion of the macula or when someone cannot have injections into the eye because of an infection or advanced glaucoma.
There are two common laser treatments. Both can help slow the worsening of wet AMD, but they don’t stop or reverse the damage.
Laser photocoagulation. In this procedure, the doctor aims a laser at leaky blood vessels to seal them and prevent further seepage. Laser photocoagulation can take only a few minutes in a doctor’s office. About half of people need follow-up treatments.
Photodynamic therapy. Here, a light-activated drug called verteporfin (Visudyne) is injected into a vein in your arm. The drug moves through your body and to your eyes. The doctor shines a light into your eyes to activate the drug. The activated drug kills abnormal blood vessels.
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