What is Age-Related Macular Degeneration?
Age-related macular degeneration (AMD)—the leading cause of vision loss for people over 60—gradually destroys the central vision needed to see objects clearly and to perform common daily tasks. AMD affects the macula, the central part of the retina, which allows us to read, drive and recognize faces. Although AMD can lead to central or legal blindness, it causes no pain, and in some cases advances so slowly that those affected notice little change in their vision. With other people, the disease progresses much faster and can lead to a loss of vision in both eyes. Those who have advanced AMD in one eye are at especially high risk of developing it in the other eye.
Although there are several subcategories, AMD is typically diagnosed as being one of two varieties, "dry" or "wet." And while there is not yet a cure for either, these two types affect vision differently and are therefore treated and managed differently.
What is dry AMD?
Most cases of AMD originate in the "dry" form which is characterized by the aging and thinning of the macular tissues. This condition typically develops slowly and results in mildly decreased vision, although some people do experience moderate or even severe visual loss with "dry" AMD. The distinguishing characteristic of the disease is tiny yellow deposits called drusen that develop under the retina and are the most common early sign of "dry" AMD.
How is dry AMD diagnosed?
Dry AMD is most often detected during a comprehensive exam with your eye care professional. After having your vision and eye pressure checked, drops are placed in your eyes to widen, or dilate, the pupils. Your retina specialist uses a special magnifying lens to examine your macula for signs of AMD (including drusen) and other eye problems. After the exam, your close-up vision may remain blurred for several hours as a result of your eyes being dilated.
How is dry AMD treated?
If your doctor notes signs of AMD during an exam, he or she will likely recommend that you start taking special vitamins. The Age-Related Eye Disease Study 2 (AREDS 2)—for which The Retina Group of Washington served as a research center—evaluated a specific combination of vitamins C and E, anti-oxidants, and the minerals zinc and copper that were found to reduce the risk of dry AMD progressing to wet AMD and its associated vision loss.
|AREDS 2 Formula||Daily Dose|
|Vitamin C||500 mg|
|Vitamin E||400 IU|
|Zinc (zinc oxide)||80 mg|
|Copper (cupric oxide)||2 mg|
The AREDS 2 formulation can be purchased at any of The Retina Group of Washington offices or over the counter at your local drug store, but be sure to ask your eye care professional to help you choose the right one from among the multitude of brands.
During an eye exam, you may be asked to look at an Amsler grid, a square of straight vertical and horizontal lines that resembles a checkerboard. Your doctor may ask you to check your vision daily with an Amsler grid at home and report any changes immediately. It is always important for patients to monitor their own vision, especially those approaching or having already passed the age of 60, or those already suffering with dry AMD. It is critical to detect and alert your doctor to even the slightest vision change that could signal the transition from dry to wet macular degeneration. If treated immediately, the onset of wet AMD can be stopped or slowed dramatically. Once dry AMD reaches the advanced stage, however, vision in many cases cannot be improved.
Directions for Use(Under a good light source/wearing reading glasses if any)
- Hold the grid approximately one foot from your face and cover one eye.
- Using the other eye, look directly at the center dot on the grid.
- Notice if any of the straight lines appear wavy or distorted, or if there are dark or blurred sections of the grid. Use this as a baseline.
- Repeat with your other eye.
- If you notice new blurry, dark or distorted sections, contact your eye doctor immediately.
The ForeseeHome AMD Monitoring Program features the FDA approved device that facilitates early detection of wet AMD. Patients at risk for developing the more serious form of the disease conduct self-tests on a home detection device that is teleconnected to a central monitoring center that reads and records the results. If even a minor change is detected, both the patient and his or her doctor are notified of the findings immediately so an exam can be conducted and, if necessary, a treatment program implemented. Further details regarding the ForeseeHome device can be found at any of our offices.
What is wet AMD?
Although only 10-15% of people with dry AMD progress to wet AMD, this form is far more serious. Wet macular degeneration begins when abnormal blood vessels grow under the macula near areas of drusen, where tissue has been eroded. These fragile vessels will leak fluid and blood, resulting in severe visual disturbances, sometimes in only a few days. Fortunately, there are multiple therapies available to treat the wet form of this devastating disease—with many more in development—thus making early detection all the more critical. Once you have wet AMD in one eye, there is a 50% chance of developing it in your other eye.
How is wet AMD diagnosed?
In addition to the comprehensive eye exam described above, your retina specialist may suggest a fluorescein angiogram if he or she has reason to suspect wet AMD may be developing. In this test, a special dye is injected into your arm and pictures are taken as the dye passes through the blood vessels in your retina. This allows your doctor to identify any leaking blood vessels and recommend immediate treatment if necessary. Sometimes a similar test with a different dye, indocyanine green, is used to identify certain sub-types of AMD. Your doctor may also recommend Ocular Coherence Tomography, or OCT, to check for AMD progression. This is a non-invasive test, similar to an ultrasound, that helps detect fluid within the macula.
How is wet AMD treated?
Wet AMD is now most often treated with new drugs injected directly into the eye. Although the idea of an eye injection may seem scary, almost all patients tolerate the procedure well. The eye is numbed before each injection and the doctor closely monitors each patient's condition following the injection. Multiple injections are often required to control wet AMD, and some patients may receive them as often as monthly. Side effects are mild and transient and include floaters, increased eye pressure, inflammation, broken blood vessel or eye pain.
How do the injected drugs work?
Abnormally high levels of vascular endothelial growth factor (VEGF) occur in eyes with wet AMD. These elevated levels of VEGF promote the growth of abnormal new blood vessels, but there are now several anti-VEGF drugs available that can help slow down vision loss from AMD, and in some cases, actually improve sight. None of these treatments, however, is a cure for the disease and vision loss may continue despite treatment. While the drugs described below are the most common treatments for wet AMD, your doctor may recommend other therapies.
This is a drug closely related to Lucentis (described below) that was approved by the Food and Drug Administration (FDA) in 2004 as an intravenous treatment for patients with advanced colorectal cancer.
So while it was first made available for what is called "off-label" use for other health conditions, it has for the last few years, been used extensively throughout the world to treat wet AMD. Recent results from The Comparisons of Age-Related Macular Degeneration Trial (CATT) demonstrated that Avastin was shown to be equally effective and safe as Lucentis. The Retina Group of Washington was one of the selected centers where the comparison of these two drugs was conducted.
Lucentis was approved by the FDA in June of 2006 for the treatment of wet AMD. Large clinical trials showed that it slows the rate of vision loss from wet AMD. In addition, over one-third of patients were found to experience significant improvement in vision.
This is the newest drug that received FDA approval in November of 2011 for the treatment of wet AMD. Eylea has similar properties as Lucentis and Avastin in attacking VEGF. The advantage is that in most cases it can be given less frequently, thus requiring fewer injections to the patient. Here again, The Retina Group of Washington was one of the centers where the evaluation of Eylea took place.
Pegaptanib Sodium (Macugen®)
Macugen in 2004 was the first FDA-approved drug for wet AMD designed to be administered by injection. It is still used for patients with allergies to the other drugs, and for others requiring long term treatment who may have serious underlying medical problems.
What other therapies exist for treating wet AMD?
Depending on the specific characteristics of your wet AMD, you and your doctor may decide on one of these treatments:
Photodynamic Therapy (PDT)
A drug called Visudyne® (Verteporfin) is injected into your arm; it travels throughout the body, "sticking" to the surface of new blood vessels. A light is then shined into your eye for approximately 80 seconds to activate the drug. This process destroys the new blood vessels and leads to a slower rate of vision loss. 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. The most common side effects in clinical trials were pain, redness, irritation or swelling at the injection site, headache, tiredness or blurred vision. Serious side effects were rare and included back pain, fainting, sweating and severe allergic reaction. Photodynamic therapy slows the rate of vision loss, but does not stop vision loss or restore vision in eyes already damaged by advanced AMD. Treatment results often are temporary, and you may need to be treated again.
This treatment can be used to destroy fragile, leaky blood vessels. A high energy beam of light is aimed directly onto the new vessels and destroys them, in an effort to prevent further loss of vision. Thermal laser treatment, however, may also destroy some surrounding healthy tissue and can impair some vision. Only a small percentage of people with wet AMD can be treated with laser surgery. The procedure is most effective if the leaky blood vessels have developed away from the fovea, the central part of the macula. The risk of new blood vessels developing after laser treatment is high. Repeated treatments may prove to be necessary, but in some cases, vision loss may progress despite repeated treatments.
What about therapies in development?
Over the years, The Retina Group of Washington has been a key participant in many national clinical trials involving the treatment of dry and wet AMD. As leaders in the D.C. metro area medical community, our physicians are up to speed on all of the latest available therapies. Ask your RGW doctor if you would be a candidate for one of our current or upcoming studies and visit our Research page for information on current or upcoming AMD studies.
What if my AMD doesn't respond to treatment?
If you have experienced some loss of vision from AMD, your eye care professional may refer you to a low vision specialist. He or she can recommend a combination of low vision services and devices that may help you make the most of your remaining vision. Closed circuit television with electronic magnification and image intensification is a commonly-used aid. A plethora of products is now available, one of the most frequently recommended of which is a lens magnifier combined with a brighter light. Most recently, an implantable telescope was FDA approved as a low vision device for patients with advanced AMD. Select patients based on specific criteria may be eligible to receive such an implant. Ask your RGW doctor if you would qualify as a candidate.
What if I have other questions about AMD?
Please contact any of the RGW offices listed on our Locations page. Any one of our retina/macula specialists would be more than happy to examine your eyes. Remember that the sooner you report visual symptoms to your doctor, the more likely he or she will be able to improve your vision.