Age-related macular degeneration (AMD) is a disease that affects your central vision. It is a common cause of vision loss among people over age of 60. Because only the center of your vision is usually affected, people rarely go blind from the disease. However, AMD can sometimes make it difficult to read, drive, or perform other daily activities that require fine, central vision.

The macula is in the center of the retina, the light-sensitive layer of tissue at the back of the eye. As you read, light is focused onto your macula. There, millions of cells change the light into nerve signals that tell the brain what you are seeing. This is called your central vision. With it, you are able to read, drive, and perform other activities that require fine, sharp, straight-ahead vision.

AMD occurs in two forms:

Although AMD can occur during middle age, the risk increases as a person gets older. Results of a large study show that people in their 50s have about a two percent chance of getting AMD. This risk rises to nearly 30 percent in those over age 75. Besides age, other AMD risk factors include:

Gender--Women may be at greater risk than men, according to some studies.

Smoking--Smoking may increase the risk of AMD.

Family History--People with a family history of AMD may be at higher risk of getting the disease.

Cholesterol--People with elevated levels of blood cholesterol may be at higher risk for wet AMD.

Neither dry nor wet AMD causes any pain. The most common symptom of dry AMD is slightly blurred vision. You may need more light for reading and other tasks. Also, you may find it hard to recognize faces until you are very close to them.

As dry AMD gets worse, you may see a blurred spot in the center of your vision. This spot occurs because a group of cells in the macula have stopped working properly. Over time, the blurred spot may get bigger and darker, taking more of your central vision.

People with dry AMD in one eye often do not notice any changes in their vision. With one eye seeing clearly, they can still drive, read, and see fine details. Some people may notice changes in their vision only if AMD affects both of their eyes.

An early symptom of wet AMD is that straight lines appear wavy. This happens because the newly formed blood vessels leak fluid under the macula. The fluid raises the macula from its normal place at the back of the eye and distorts your vision. Another sign that you may have wet AMD is rapid loss of your central vision. This is different from dry AMD in which loss of central vision occurs slowly. As in dry AMD, you may also notice a blind spot.

Normal vision.

The same scene as it might be
viewed by a person with AMD.

If you notice any of these changes in your vision, contact your eye care professional at once for an eye exam.

Eye care professionals detect AMD during an eye examination that includes:

Visual acuity test: This eye chart test measures how well you see at various distances.

Pupil dilation: This examination enables your eye care professional to see more of the retina and look for signs of AMD. To do this, drops are placed into the eye to dilate (widen) the pupil. After the examination, your vision may remain blurred for several hours.

One of the most common early signs of AMD is the presence of drusen. Drusen are tiny yellow deposits in the retina. Your eye care professional can see them during an eye examination. The presence of drusen alone does not indicate a disease, but it might mean that the eye is at risk for developing more severe AMD.

While conducting the examination, your eye care professional may ask you to look at an Amsler grid. This grid is a pattern that resembles a checkerboard. You will be asked to cover one eye and stare at a black dot in the center of the grid. While staring at the dot, you may notice that the straight lines in the pattern appear wavy to you. You may notice that some of the lines are missing. These may be signs of wet AMD (See Amsler Grid below.)

If your eye care professional suspects you have wet AMD, you may need to have a test called fluorescein angiography. In this test, a special dye is injected into a vein in your arm. Pictures are then taken as the dye passes through the blood vessels in the retina. The photos help your eye care professional evaluate leaking blood vessels to determine whether they can be treated.

On the left is what an Amsler grid normally looks like, and the illustration on the right is how it might look to someone with AMD. These grids are reduced in size; ask your doctor for a full-size grid to use at home.

Dry AMD currently cannot be treated. But this does not mean that you will lose your sight. Fortunately, dry AMD develops very slowly. You may lose some of your central vision over the years. However, most people are able to lead normal, active lives--especially if AMD affects only one eye.

Some cases of wet AMD can be treated with laser surgery. The treatment involves aiming a high energy beam of light directly onto the leaking blood vessels. Laser treatment is more effective if the leaky blood vessels have developed away from the fovea--the central part of the macula. But even if the blood vessels are growing right behind the fovea, the treatment can be of some value in stopping further vision loss.

Laser surgery is performed in your eye care professional's office or eye clinic. Before the surgery, he or she will: (1) dilate your pupil and (2) apply drops to numb the eye. In some cases, he or she also may numb the area behind the eye to prevent any discomfort.

The lights in the office will be dim. As you sit facing the laser machine, your eye care professional will hold a special lens to your eye. You may see flashes of light.

You can leave the office once the treatment is done, but you will need someone to drive you home. Because your pupils will stay dilated for a few hours, you also should bring a pair of sunglasses.

For the rest of the day, your vision may be a little blurry. Your eye may also hurt a bit. This is easily controlled with drugs that your eye care professional can suggest.

You will need to make frequent follow-up visits. During each exam, you may have fluorescein angiography to make sure that the blood vessels are not still leaking, or that new blood vessels have not developed. If the vessels continue to leak, you might need some more laser surgery. It is important to realize that laser surgery is not a cure for AMD. It is only a treatment to help stop further vision loss. The risk of new blood vessels growing back after laser treatment is relatively high.

The National Eye Institute (NEI) is the Federal government's lead agency for vision research. The NEI is supporting a number of research studies both in the laboratory and with patients to learn more about the cause of AMD. This research should provide better ways to detect, treat, and prevent vision loss in people with the disease.

Findings from the NEI-sponsored Age-Related Eye Disease Study (AREDS) showed that high levels of antioxidants and zinc significantly reduces the risk of advanced age- related macular degeneration (AMD) by about 25 percent.

Scientists have begun to study the possibility of transplanting healthy cells into a diseased retina. Although this work is at a very early stage and still experimental, someday it may help people keep their vision or restore some lost vision.

Normal use of your eyes will not cause further damage to your vision. Even if you have lost sight to AMD, you should not be afraid to use your eyes for reading, watching TV, and other usual activities.

Low vision aids are available to help you make the most of your remaining vision. Low vision aids are special lenses or electronic systems that make images appear larger. If you need low vision aids, your eye care professional can often prescribe them or refer you to a low vision specialist. In addition, groups and agencies that offer information about counseling, training, and other special services are available. You may also want to contact a nearby school of medicine or optometry as well as a local agency devoted to helping the visually impaired.