Adult Macular Degeneration (AMD)
Definition |
Causes |
Risk Factors |
Symptoms |
Diagnosis |
Treatment |
Prevention |
Organizations
Definition
Macular degeneration is deterioration of the macula. The macula is a tiny structure in the middle of the retina that helps produce central vision. The retina is a tissue that lines the back of the eye and sends visual signals to the brain. Macular degeneration causes a gradual destruction of sharp, central vision.
There are four types of macular degeneration:
- Adult - age 55 and older (most common type)
- Late Onset - age 30s-40s
- Middle Onset - age 5-20
- Early Onset - birth to age 7
Adult macular degeneration (AMD) occurs in two forms:
Dry AMD
Ninety percent of all people with AMD have this type. An area of the retina becomes diseased, leading to the slow breakdown of cells in the macula, and a gradual loss of central vision.
Wet AMD
Although only 10% of all people with AMD have this type, it accounts for 90% of all blindness from the disease. As dry AMD worsens, new blood vessels may begin to grow and cause "wet" AMD. These new blood vessels often leak blood and fluid under the macula. This causes rapid damage to the macula that can lead to loss of central vision in a short time.
Causes
The cause of adult macular degeneration is not known.
Risk Factors
A risk factor is something that increases your chance of getting a disease or condition.
- Age: 60 or older
- Sex: Female
- Race: White
- Smoking
- Family members with AMD
Symptoms
In some people, macular degeneration advances so slowly that it has little effect on their vision. But in others, the disease progresses faster and may lead to vision loss. Both dry and wet AMD cause no pain.
Symptoms include:
- Blurred vision (an early sign)
- Difficulty seeing details in front of you, such as faces or words in a book
- Blurred vision that goes away in brighter light
- A small, but growing blind spot in the middle of the field of vision
- Straight lines appear crooked (symptom of wet AMD)
Diagnosis
The doctor will ask about your symptoms and medical history, and perform a physical exam. The doctor may suspect AMD if you are over age 60 and have had recent changes in your central vision. To look for signs of the disease, an ophthalmologist or optometrist will use eye drops to dilate, or enlarge, your pupils to view the back of the eye.
You may also be asked to view an Amsler grid, a pattern that looks like a checkerboard. Early changes in your central vision will cause the grid to appear distorted, a sign of AMD.
Treatment
Treatment may include:
Dry AMD
There is currently no treatment for dry AMD. It has been suggested that taking certain vitamins and minerals may slow the progress of the disease, but more research is needed.
Wet AMD
Some cases of wet AMD can be treated with laser surgery. This treatment involves aiming a strong light beam onto the new blood vessels to destroy them. Laser surgery is a short procedure performed by ophthalmologists in their offices or in eye clinics.
Prevention
There are no guidelines for preventing adult macular degeneration because the cause is unknown. If you have dry AMD or are age 60 or older, you should have your eyes examined by an eye care professional at least once a year. Surgery can prevent wet AMD from completely destroying your central vision
Organizations
American Macular Degeneration Foundation
http://www.macular.org/
Macular Degeneration Foundation
http://www.eyesight.org/
SOURCES:
National Eye Institute
Macular Degeneration Foundation
Last reviewed June 2001 by Medical Review Board
