Diagnosing AMD
This is why Macular Degeneration is so dangerous, both dry and
wet AMD cause no pain.
For dry AMD: the most common early sign is blurred vision. As
fewer cells in the macula are able to function, people will see details
less clearly in front of them, such as faces or words in a book.
Often this blurred vision will go away in brighter light. If the loss
of these
light-sensing cells becomes great, people may see a small--but
growing--blind spot in the middle of their field of vision.
For wet AMD: the classic early symptom 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, resulting in loss of one's central vision.
How is AMD detected?
Your eye care professional 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, he or she will use eye drops to dilate, or enlarge,
your pupils. Dilating the pupils allows your eye care professional
to view the back of the eye better.
AMD is detected during a comprehensive eye exam that includes:
1. Visual acuity test. This eye chart test measures how well you see
at various distances.
2. Dilated eye exam. Drops are placed in your eyes to widen, or dilate,
the pupils. Your eye care professional uses a special magnifying
lens to examine your retina and optic nerve for signs of AMD and other
eye problems. After the exam, your close-up vision may
remain blurred for several hours.
3. Tonometry. An instrument measures the pressure inside the eye.
Numbing drops may be applied to your eye for this test.
The doctors at Eye Care Surgery Center may do other tests to learn
more about the structure and health of your eye.
During an eye exam, you may be asked to look at an Amsler grid.
The pattern of the grid resembles a checkerboard. You will 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. You may notice that some of the lines are missing. These may
be signs of AMD.
If the doctors at Eye Care Surgery Center think you need treatment for
wet AMD, he or she may suggest a fluorescein angiogram.
In this test, a special dye is injected into your arm. Pictures are taken as
the dye passes through the blood vessels in your retina. The test allows
your eye care professional to identify any leaking blood vessels and
recommend treatment.
How is wet AMD treated?
Wet AMD can be treated with laser surgery, photodynamic therapy, and i
njections into the eye. None of these treatments is a cure for wet AMD.
The disease and loss of vision may progress despite treatment.
1. Laser surgery. This procedure uses a laser to destroy the fragile, leaky
blood vessels. A high energy beam of light is aimed directly onto the
new blood vessels and destroys them, preventing further loss of vision. However, laser treatment may also destroy some surrounding healthy
tissue and some vision. Only a small percentage of people with wet AMD can be treated with laser surgery. Laser surgery is more effective if
the leaky blood vessels have developed away from the fovea, the central part of the macula. Laser surgery is performed in a doctor's office or eye clinic.
The risk of new blood vessels developing after laser treatment is high. Repeated treatments may be necessary. In some cases, vision loss may
progress despite repeated treatments.
2. Photodynamic therapy. A drug called verteporfin is injected into your arm. It travels throughout the body, including the new blood vessels in your eye.
The drug tends to "stick" to the surface of new blood vessels. Next, a light is shined into your eye for about 90 seconds. The light activates the drug.
The activated drug destroys the new blood vessels and leads to a slower rate of vision decline. Unlike laser surgery, this drug does not destroy surrounding
healthy tissue. Because the drug is activated by light, you must avoid exposing your skin or eyes to direct sunlight or bright indoor light for five days after treatment.
Photodynamic therapy is relatively painless. It takes about 20 minutes and can be performed in a doctor's office.
Photodynamic therapy slows the rate of vision loss. It does not stop vision loss or restore vision in eyes already damaged by advanced AMD.
Treatment results often are temporary. You may need to be treated again.
3. Injections. Wet AMD can now be treated with new drugs that are injected into the eye (anti-VEGF therapy). Abnormally high levels of a specific
growth factor occur in eyes with wet AMD and promote the growth of abnormal new blood vessels. This drug treatment blocks the effects of the growth factor.
You will need multiple injections that may be given as often as monthly. The eye is numbed before each injection. After the injection, you will remain in
the doctor's office for a while and your eye will be monitored. This drug treatment can help slow down vision loss from AMD and in some cases improve sight.
How is dry AMD treated?
Once dry AMD reaches the advanced stage, no form of treatment can prevent vision loss. However, treatment can delay and possibly prevent
intermediate AMD from progressing to the advanced stage, in which vision loss occurs.
and zinc significantly reduces the risk of advanced AMD and its associated vision loss. Slowing AMD's progression from the intermediate
stage to the advanced stage will save the vision of many people.
Age-Related Eye Disease Study (AREDS)
What is the dosage of the AREDS formulation?
The specific daily amounts of antioxidants and zinc used by the study researchers were 500 milligrams of vitamin C, 400 International Units of
vitamin E, 15 milligrams of beta-carotene (often labeled as equivalent to 25,000 International Units of vitamin A), 80 milligrams of zinc as zinc
oxide, and two milligrams of copper as cupric oxide. Copper was added to the AREDS formulation containing zinc to prevent copper deficiency
anemia, a condition associated with high levels of zinc intake.
Who should take the AREDS formulation?
People who are at high risk for developing advanced AMD should consider taking the formulation. You are at high risk for developing advanced
AMD if you have either:
1. Intermediate AMD in one or both eyes.
OR
2. Advanced AMD (dry or wet) in one eye but not the other eye.
Your eye care professional can tell you if you have AMD, its stage, and your risk for developing the advanced form.
The AREDS formulation is not a cure for AMD. It will not restore vision already lost from the disease. However, it may delay the onset of
advanced AMD. It may help people who are at high risk for developing advanced AMD keep their vision.
Can people with early stage AMD take the AREDS formulation to help prevent the disease from progressing to the intermediate stage?
There is no apparent need for those diagnosed with early stage AMD to take the AREDS formulation. The study did not find that the formulation
provided a benefit to those with early stage AMD. If you have early stage AMD, a comprehensive dilated eye exam every year can help determine
if the disease is progressing. If early stage AMD progresses to the intermediate stage, discuss taking the formulation with your doctor.
Can diet alone provide the same high levels of antioxidants and zinc as the AREDS formulation?
No. The high levels of vitamins and minerals are difficult to achieve from diet alone. However, previous studies have suggested that people who
have diets rich in green leafy vegetables have a lower risk of developing AMD.
Can a daily multivitamin alone provide the same high levels of antioxidants and zinc as the AREDS formulation?
No. The formulation's levels of antioxidants and zinc are considerably higher than the amounts in any daily multivitamin.
If you are already taking daily multivitamins and your doctor suggests you take the high-dose AREDS formulation, be sure to review all
your vitamin supplements with your doctor before you begin. Because multivitamins contain many important vitamins not found in the AREDS
formulation, you may want to take a multivitamin along with the AREDS formulation. For example, people with osteoporosis need to be particularly
concerned about taking vitamin D, which is not in the AREDS formulation.
How can I take care of my vision now that I have AMD?
Dry AMD. If you have dry AMD, you should have a comprehensive dilated eye exam at least once a year. Your eye care professional can monitor
your condition and check for other eye diseases. Also, if you have intermediate AMD in one or both eyes, or advanced AMD in one eye only,
your doctor may suggest that you take the AREDS formulation containing the high levels of antioxidants and zinc.
Because dry AMD can turn into wet AMD at any time, you should get an Amsler grid from your eye care professional. Use the grid every day to
evaluate your vision for signs of wet AMD. This quick test works best for people who still have good central vision. Check each eye separately.
Cover one eye and look at the grid. Then cover your other eye and look at the grid. If you detect any changes in the appearance of this grid or
in your everyday vision while reading the newspaper or watching television, get a comprehensive dilated eye exam.
Wet AMD. If you have wet AMD and your doctor advises treatment, do not wait. After laser surgery or photodynamic therapy, you will need
frequent eye exams to detect any recurrence of leaking blood vessels. Studies show that people who smoke have a greater risk of recurrence
than those who don't. In addition, check your vision at home with the Amsler grid. If you detect any changes, schedule an eye exam immediately.
What can I do if I have already lost some vision from AMD?
If you have lost some sight from AMD, don't be afraid to use your eyes for reading, watching TV, and other routine activities. Normal use of your
eyes will not cause further damage to your vision.
If you have lost some sight from AMD, ask your eye care professional about low vision services and devices that may help you make the most of
your remaining vision. Ask for a referral to a specialist in low vision. Many community organizations and agencies offer information about low vision
counseling, training, and other special services for people with visual impairments. A nearby school of medicine or optometry may provide low
vision services.
Current Research
What research is being done?
The National Eye Institute is conducting and supporting a number of studies to learn more about AMD. For example, scientists are:
- Studying the possibility of transplanting healthy cells into a diseased retina.
- Evaluating families with a history of AMD to understand genetic and hereditary factors that may cause the disease.
- Looking at certain anti-inflammatory treatments for the wet form of AMD.
This research should provide better ways to detect, treat, and prevent vision loss in people with AMD.
