Age-Related Macular Degeneration
What is age-related macular degeneration?
Age-related macular degeneration (AMD) is damage to the part of the eye called the macula. It is in the center of the retina. The retina is light-sensitive tissue at the back of the eye. Cells in the retina change light into impulses that are sent to the brain. The brain interprets them as images. If the macula is damaged, you can no longer see fine detail in the center of your vision. Usually your side (peripheral) vision is not affected. However, the loss of central vision can make it difficult to read, drive, or see straight ahead.
AMD is a common problem for many people as they get older. It usually affects both eyes, but one eye may be affected before the other.
How does it occur?
There are two forms of AMD: wet and dry. The wet form occurs when new, fragile blood vessels grow beneath the retina and leak blood and fluid. The leaks can rapidly damage the macula. In the dry form, the light-sensitive cells in the macula gradually break down. In both cases, a blind spot forms in or near the center of vision. The dry form is more common and causes a slower and often less severe loss of vision.
The cause of these changes is not known. Smoking may contribute to the problem. You may also be at greater risk if you have family members with AMD.
What are the symptoms?
AMD does not cause pain. The first signs of the condition are usually problems with your vision. Symptoms may include:
- blurred vision
- wavy appearance to straight lines (for example, a telephone pole may appear to be bent)
- a dark patch in the middle of words as you read
- a worsening of your color vision.
If just one eye is affected, you may not notice the loss of vision when you are using both eyes.
How is it diagnosed?
Your health care provider will review your symptoms and examine your eyes with a lighted tool called an ophthalmoscope. You may need a special test called fluorescein angiography by a medical eye doctor. In this test dye is put into a vein in your arm. The dye travels to blood vessels in your retina. Then pictures are taken of your retina. The pictures will show where the leaking blood vessels are behind your retina.
How is it treated?
If the leaking vessels are not in the center of the macula, the wet form of AMD can sometimes be treated by sealing the leaking vessels with a thermal laser. This may prevent further damage to the retina, particularly if the condition is caught early. Sealing blood vessels may leave a small blind spot near the center of your vision.
The center of the macula is very important for good vision. If the leaking vessels are directly in the center of the macula, a thermal laser treatment would cause too much vision loss. In this case, a treatment called photodynamic therapy may be used. For this procedure, a laser-activated dye is injected into your bloodstream. When the dye reaches the retina, a weak laser is used to damage the leaking blood vessels. These blood vessels grow back, so the procedure must be repeated 5 or 6 times in the next 2 years. However, in some cases of wet AMD, this treatment will reduce the amount of vision loss you will have compared to having no treatment.
The risk of vision loss from dry AMD can sometimes be decreased with a vitamin and mineral supplement. Talk to your health care provider about the risks and benefits of this treatment.
If you have either form of AMD, low vision aids may help you with your daily activities. Low vision aids include such things as:
- magnifying glasses and telescopes
- closed-circuit TV
- clocks and phones with large numbers and reading material printed in large type.
Ask your health care provider for help in finding which low vision aids may be helpful for you.
How can I take care of myself?
- Tell your doctor if your vision changes in any way.
- Never ignore blurred vision, lines that appear wavy, blind spots, or loss of color vision.
- Have a complete eye exam every 2 or 3 years. If you have diabetes or a family history of eye disease, have your eyes checked at least once a year.
