Age-related macular degeneration (AMD) is a deterioration or breakdown of the eye’s macula. The macula is a small area in the retina – the light-sensitive tissue lining the back of the eye. The macula is the part of the retina that is responsible for your central vision, allowing you to see fine details clearly.
AMD is a common eye condition among people age 50 and older. It is a leading cause of vision loss in older adults. As people get older, the risk increases. Other risk factors include the following:
- Smoking. Research shows that smoking increases the risk of AMD two-fold.
- Race. Caucasians are much more likely to get AMD than people of African American descent.
- Family History. People with a family history of AMD are at a higher risk.
In some people, AMD advances so slowly that vision loss does not occur for a long time. In others, the disorder progresses faster and may lead to a loss of vision in one or both eyes. The vision loss makes it difficult to recognize faces, drive a car, read, print, or do close work, such as sewing or fixing things around the house.
Despite the limited vision, AMD does not cause complete blindness. You will be able to see using your side (peripheral) vision.
How is AMD detected?
The early and intermediate stages of AMD usually start without symptoms. Only a comprehensive dilated eye exam can detect AMD. The eye exam may include the following:
- Visual acuity test. This eye chart measures how well you see at distances.
- Dilated eye exam. Your eye care professional places drops in your eyes to widen or dilate the pupils. This gives him or her a better view of the back of your eye. Using a special magnifying lens, he or she then looks at your retina and optic nerve for signs of AMD and other eye problems.
- Amsler grid. Your eye care professional also may ask you to look at an Amsler grid. Changes in your central vision may cause the lines in the grid to disappear or appear wavy, a sign of AMD.
- Fluorescein angiogram. Your eye care professional may suggest you see an ophthalmologist to perform a fluorescein angiogram. With this test, your doctor injects a dye into your arm. Pictures are taken as the dye passes through the blood vessels in your eye. The test allows your doctor to identify leaking blood vessels and decide the best treatment.
Two forms of AMD that can cause vision loss:
Dry and Wet
Dry AMD is the most common form of AMD in its early or intermediate stages. It occurs in about 90 percent of the people with the condition.
Dry AMD happens when the light-sensitive cells in the macula slowly break down, gradually blurring central vision in the affected eye. As dry AMD progresses, you may see a blurred spot in the center of your vision. Your eye care professional may call this “geographic atrophy.”
Over time, central vision in the affected eye can be slowly lost as less of the macula works.
Symptoms of Dry AMD
Dry AMD has few symptoms in the early stages. It is important to have your eyes examined regularly before the disease progresses.
In the later stages, blurred vision is the most common symptom of dry AMD. Objects also may not appear to be as bright as they used to be.
As a result, you may have trouble recognizing faces. You may need more light for reading and doing other tasks. Both eyes can have dry AMD or one eye can be affected first.
Vision loss and Dry AMD
If you have vision loss from dry AMD in one eye only, you may not notice any changes in your overall vision. With the other eye seeing clearly, you still can drive, read, and see fine details.
You may notice changes in your vision if dry AMD affects both eyes or if you develop the wet form of the disease. In any case, see an eye care professional for a comprehensive dilated eye exam if blurring occurs in your vision.
Can the dry form turn into the wet form?
All people who have the wet form had the intermediate stage of the dry form first. The dry form also can suddenly turn into the wet form, even during early stage AMD. Eye care professionals have no way to tell if the dry form will turn into the more severe wet form.
Dry AMD can turn into wet AMD at any time. You should get an Amsler grid from your eye care professional to check your vision for signs of wet AMD.
Diet might help
Studies have shown that people who eat a diet rich in green, leafy vegetables and fish have a lower risk of developing AMD.
While there is no definitive proof that changing your diet will reduce your risk of developing AMD or having it progress, to maintain good health in general, there is no reason not to eat a healthy diet, exercise, avoid smoking, and see your healthcare professional regularly.
Here is what an Amsler grid normally looks like.
This is what an Amsler grid might look like to someone with AMD.
A note about early stage dry AMD
Currently, no treatment exists for early stage dry AMD, which in many people shows no symptoms or loss of vision. Your eye care professional may recommend that you get a comprehensive dilated eye exam at least once a year. The exam will help determine if your condition is advancing.
If your condition gets worse, your eye care professional may suggest that you take a specific high-dose supplement that contains antioxidants and zinc. Do not take these high-dose supplements unless your doctor recommends them. Research shows that high doses of specific vitamins and minerals may slow the condition’s progress.
What is wet AMD?
Wet AMD affects about 10 percent of all people with AMD. This type, however, is more severe than the early and intermediate stages of the dry form.
Wet AMD happens when abnormal blood vessels behind the retina start to grow under the macula. These new blood vessels can be fragile and leak blood and fluid. The blood and fluid cause the macula to swell and damage occurs rapidly. The damage may also cause scarring of the retina.
Although loss of central vision can happen quickly, eye care professionals can slow down or stop the progression of wet AMD if it is detected before severe vision loss occurs.
What are the symptoms?
During the early stages of wet AMD straight lines may appear wavy. People with wet AMD also may develop a blind spot, which results in the loss of central vision.
If you notice these or other changes to your vision, contact your eye care professional at once. Again, eye care professionals may be able to treat the condition before severe vision loss occurs.
Treatment options for wet AMD
With early diagnosis and proper treatment, you can delay the progression of AMD. The earlier it is detected, the better your chances of keeping your vision. Wet AMD typically results in severe vision loss. However, eye care professionals can try different therapies to stop further vision loss. You should remember that the therapies described below are not a cure. The condition may progress even with treatment.
- Injections. One option to slow the progression of wet AMD is to inject drugs into your eye. With wet AMD, abnormally high levels of vascular endothelial growth factor (VEGF) are secreted in your eyes. This substance promotes the growth of new abnormal blood vessels. The anti-VEGF injection therapy blocks its effects. If you get this treatment, you may need multiple injections. Your eye care professional may give them monthly. Before each injection, your eye care professional will numb your eye and clean it with antiseptics. To prevent the risk of infection, a doctor may prescribe antibiotic drops.
- Photodynamic therapy. This technique involves laser treatment of select areas of the retina. First, a drug called verteporfin will be injected into a vein in your arm. The drug travels through the blood vessels in your body, including any new, abnormal blood vessels in your eye. Your eye care professional then shines a laser beam into your eye to activate the drug in the blood vessels. Once activated, the drug destroys the new blood vessels and slows the rate of vision loss. This procedure takes about 20 minutes.
- Laser surgery. Eye care professionals sometimes treat certain cases of wet AMD with laser surgery, though this is less common than other treatments. This treatment is performed in a doctor’s office or eye clinic. It involves aiming an intense beam of light at the new blood vessels in your eyes to destroy them. However, laser treatment also may destroy some surrounding healthy tissue and cause more blurred vision.
What is advanced AMD?
Both the wet form and the advanced dry form are considered advanced AMD. It can occur in the same eye or an eye may have just one form or the other. In most cases, only advanced AMD can cause vision loss.
People who have advanced AMD in one eye are at especially high risk of developing advanced AMD in the other eye.
However, research has shown that high doses of vitamins and mineral supplements may slow the progression of intermediate AMD to the more advanced stage.
A note about the AREDS formulation
Researchers stress that the AREDS formulation is not a cure. It will not restore vision already lost from the condition. But it may delay the onset of advanced AMD. It also may help people who are at a high risk of developing advanced AMD keep their remaining vision.
Loss of Vision
Coping with AMD and vision loss can be a traumatic experience. This is especially true of those who have just begun to lose their vision or have low vision. Having low vision means that even with regular glasses, contact lenses, medicine, or surgery, people find everyday tasks difficult to do. Reading the mail, shopping, cooking, seeing the TV, and writing can all seem challenging.
However, help is available. You may not be able to restore your vision, but low vision services can help you make the most of what is remaining. You can continue enjoying friends, family, hobbies, and other interests just as you always have. The key is not delaying use of these services.