Age-Related Macular Degeneration (AMD)
Age-related macular degeneration is a common eye disease that may damage central vision as you age. Central vision is needed for seeing objects clearly and for common daily tasks such as reading and driving. In some people, AMD advances so slowly that it has little effect on their vision. In others, the disease progresses faster and may lead to a loss of vision in one or both eyes. People over sixty are at greater risk than other age groups.
How does AMD Damage Vision?
The retina is a paper-thin tissue that lines the back of the eye. Visual signals are sent to the brain. In the middle of the retina is a tiny area called the macula. The macula is made up of millions of light-sensing cells that help to produce central vision. Damage to these cells causes a decrease in central vision.
AMD Occurs in Two Forms
Ninety percent of all people with AMD have this type. Scientists are still not sure what causes dry AMD. Studies suggest that an area of the retina becomes diseased. This will lead to the slow breakdown of the light-sensing cells in the macula and a slow loss of central vision.
Although only 10 percent of all people with AMD have this type, it accounts for 90% of severe vision loss from the disease. As dry AMD worsens, new blood vessels may begin to grow and cause “wet” AMD. Because these new blood vessels tend to be very fragile, they will often leak blood and fluid under the macula. This causes rapid damage to the macula that can lead to the loss of central vision in a short period of time.
What Are the Symptoms?
Macular degeneration is painless. With the dry form develops slowly. With the wet form, visual symptoms can happen faster. Symptoms for both forms are:
- Blurred or cloudy vision.
- Seeing a dark or blind spot at the center of vision.
- Distorted vision such as straight lines that look wavy.
- Trouble reading or doing other close-up work.
- Trouble doing any activity that requires sharp vision (e.g. driving).
- Complete loss of central vision. Peripheral or side vision is not affected.
The classic early symptom of wet AMD is that straight lines appear crooked. This results when fluid from the leaking blood vessels gathers and lifts the macula, distorting vision. A small blind spot may also appear in wet AMD; this results in loss of one’s central vision.
Treatment of AMD
For patients with dry AMD, a major national study called the Age-Related Eye Disease Study (AREDS) noted that high doses of the antioxidant vitamins A, C, and E along with zinc slowed down the progress of macular degeneration. This dietary supplement lowered the risk of macular degeneration progressing to advanced stages by about 25 percent. The daily supplements also reduced the risk of vision loss. The supplements did not seem to help people with minimal macular degeneration or people without signs of the disease while in the study.
There are many different brands of AREDS vitamins for the eyes. Your eye doctor can tell you about some.
The standard treatment for wet AMD is to inject medication into the eye. The type of medication is called anti-vascular endothelial growth factor, or anti-VEGF, drugs. Blocking VEGF reduces the growth of abnormal blood vessels, slows their leakage, helps to slow vision loss, and in some cases improves vision.
Your ophthalmologist administers the anti-VEGF drug directly to your eye in an outpatient procedure. Before the procedure, your ophthalmologist will clean your eye to prevent infection and will use an anesthetic drop to numb your eye. The injection is performed with a very fine needle. You may receive multiple anti-VEGF injections over the course of many months. Repeat anti-VEGF treatments are often needed for continued benefit. There are currently 3 different types of anti-VEGF medication now available. Your doctor will need to determine which medication will work best for you.
In some cases, your ophthalmologist may want to combine anti-VEGF treatment with other therapies. The treatment that’s right for you will depend on the specific condition of your macular degeneration.
Low vision aids are often helpful. Different devices are available for different tasks. Training and practice are important in order to become good at using any device. The University of Wisconsin Ophthalmology Clinic provides a low vision service that will show you aids and advise you which may be helpful to you.
Please call the Ophthalmology Clinic at (608) 263-7171 if you have any questions or concerns, or wish to schedule a clinic visit.
The Spanish version of this Health Facts for You is #7271.
The information provided should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Any duplication or distribution of the information contained herein is strictly prohibited.
Last Updated: 01/16/2013
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