Overview
What Is It?
Macular degeneration is a group of eye diseases that affects central vision. It affects the macula, the central part of the retina of the eye that allows you to see fine, sharp details straight ahead.
Macular degeneration is a group of eye diseases that affects central vision. According to the National Eye Institute, it is the leading cause of severe vision loss among people age 60 and older, especially among Caucasians. The disease tends to occur more often in women than in men.
Macular degeneration often is called age-related macular degeneration (AMD) because the greatest risk factor for the disease is advancing age. Although AMD can occur in middle age, the National Eye Institute reports that people age 60 and older are at greatest risk for developing AMD. According to the American Macular Degeneration Foundation, macular degeneration affects more than 10 million Americans.
Some forms of macular degeneration can occur in children. One is juvenile macular degeneration, or Stargardt's disease, which affects one in 10,000 children, according to the American Macular Degeneration Foundation; it usually appears between the ages of six and 20 and is inherited. A gene that causes Stargardt's disease has been identified.
Genetic and other risk factors
If you have a parent or sibling with age-related macular degeneration, you are at a higher risk of developing the disease yourself.
As the federal government's lead agency on vision research and sponsor of continuing studies on AMD, the National Eye Institute says its research so far indicates the following additional risks for macular degeneration:
- obesity (Research studies suggest a link between obesity and the progression of early and intermediate-stage AMD to advanced AMD.)
- Caucasian ethnicity
- being female
- a family history of the condition
- smoking
- high blood cholesterol levels
- cardiovascular disease
- hypertension
Symptoms
Macular degeneration affects the macula, the central part of the retina of the eye that allows you to see fine, sharp details straight ahead. The retina is made of light-sensitive tissue that sends visual messages via nerve impulses to the brain through the optic nerve. The brain then processes the nerve signals into a "picture" that you see. The macula consists of millions of light-sensitive cells that help provide the central vision used in reading, driving, recognizing faces and doing close work, such as sewing. As the macula deteriorates, central vision becomes blurred and distorted. Difficulty reading, distortion of letters, a greater need for more light to see, reduced color vision and the loss of ability to see fine detail are other symptoms of macular degeneration. Pain is not a symptom. Although peripheral, or side, vision usually is not affected by macular degeneration, and people rarely go totally blind from the disease, it can severely hamper daily activities because of the loss of fine, central sight.
The two common types of macular degeneration are "dry" and "wet." According to the National Eye Institute, more than 85 percent of people who have macular degeneration have the dry, or atrophic, form. The light-sensitive cells in the macula slowly break down in this form of the disease, resulting in a gradual loss of central vision over a period of many years. Dry macular degeneration often first occurs in just one eye. The disease may or may not affect the other eye later. Although researchers continue to study the disease, the exact cause of dry macular degeneration is unknown, and there is no cure. There also is no effective treatment to stop the gradual loss of detailed central vision. However, studies suggest that high dose vitamins C, E, beta carotene and zinc (along with copper) may slow the progression of dry AMD.
The early warning sign of dry macular degeneration is blurred or distorted vision. As cells in the macula deteriorate, fewer details can be seen clearly when looking straight ahead. Often, bright light, by improving contrast, can enable patients to see better, although their vision will still be blurred. As the light-sensitive cells die, a small blind spot may appear in the middle of the vision field. Over the course of many years, the blind spot may increase in size with an accompanying decrease in the central visual acuity.
The wet form of macular degeneration occurs only in about 10 to 15 percent of people with the disease, but it accounts for two-thirds of advanced AMD and, therefore, leads to significantly more severe vision loss from AMD than the dry form, according to the National Eye Institute. The wet form occurs when new, abnormal blood vessels grow under the retina. The blood vessel growth is called subretinal or choroidal neovascularization. These weak blood vessels may leak fluid and bleed, causing the macula to bulge or lift up in the eye, damaging it and distorting vision. As with dry macular degeneration, this may produce the symptom of straight lines appearing wavy. Wet macular degeneration may also cause a blind spot to develop. Central vision can be destroyed in a short time, sometimes as fast as within weeks to months, or it can take longer.
Diagnosis
Your health care professional can detect macular degeneration through a comprehensive eye examination that includes reviewing your and your family's medical history and conducting several tests. The following are common tests for age-related macular degeneration (AMD):
- Visual acuity measurement. This test measures your central vision's ability to distinguish details and shapes. You will be asked to look at and read a chart to measure how well you see at various distances.
- Dilated eye exam. Your health care professional will place drops in your eyes to widen, or dilate, your pupils, and use an instrument called an ophthalmoscope to view the interior of the eye to look through the pupil at the retina. Your near vision may be blurred for several hours after this examination until the pupil-dilating drops wear off. This test can help your health care professional detect small, yellow-colored deposits in the retina, called drusen, which can be an early sign of dry AMD. These deposits are composed of degenerative material from the retina's light-sensitive cells. The deposits are thought to interfere with the function of the macula, possibly causing its deterioration. But, drusen can be present without loss of vision. If your health care professional finds drusen, it doesn't necessarily mean you have macular degeneration. It means that eye is at risk for developing the disease.
- Amsler grid. In this test, you look at a grid that is a pattern of horizontal and vertical intersecting lines, similar to graph paper. You cover one eye and stare with the other at a black dot in the center of the grid. If, while staring at the dot, you notice that straight lines appear wavy, and/or some of the lines are missing, you may have a symptom of AMD.
You can obtain an Amsler grid from your health care professional and do this simple test yourself to monitor symptoms of wet AMD. It is not, however, a substitute for a complete eye examination or a diagnosis by your health care professional. It may help you detect subtle changes in your vision that should be pointed out to your health care professional. Talk to your health care professional about whether using an Amsler grid is right for you.
- Fluorescein angiography. In this procedure, a vegetable dye is injected into your arm and travels to the retina. A special camera takes pictures of your retina as the dye passes through it. This technique maps the blood flow in the eye and can show any abnormal leakage or changes in the retina. The results help your health care professional confirm whether you have wet AMD. The procedure also helps your health care professional evaluate the damage and determine whether the leaking blood vessels can be treated.
- Tonometry. An instrument measures the pressure inside your eye. Numbing drops may be placed in your eyes for this test.
Treatment
If you are at high risk for developing advanced AMD—that is, you have intermediate AMD or advanced AMD in one eye (wet or dry)—talk to your health care professional about taking high doses of certain vitamin/mineral supplements. The Age-Related Eye Disease Study (AREDS), sponsored by the National Eye Institute, followed 3,640 participants who had at least early AMD for at least five years. Those at high risk for developing advanced AMD—those with intermediate AMD and with advanced AMD in one eye only—reduced their risk of developing advanced stages of AMD about 25 percent when they took daily antioxidant/mineral supplements containing 500 mg vitamin C, 400 IU vitamin E, 15 mg beta-carotene, 80 mg zinc (as zinc oxide) and 2 mg copper (as cupric oxide). Smokers should not take this preparation, and all patients should consult their personal physician about all vitamin usage.
In addition, a study done by researchers at Brigham Young University and Weill Medical College of Cornell University found that when consumed in antioxidant-rich foods like pecans, blueberries and artichokes, antioxidants extend the lifetime of crucial retinal cells and disrupt two processes in the retina that contribute to macular degeneration. Omega-3 fatty acids, such as from oily fish, may also be helpful.
Some cases of the wet form of age-related macular degeneration (AMD) can be treated with laser surgery, but treatment may not restore lost vision. Treatment slows the rate of vision loss and may help preserve some central sight. For treatment to be effective and help protect the vision you have, it is vital that wet AMD be caught early, before it spreads to a part of the macula where treatment is not an option and before it destroys central vision.
Laser surgery destroys the leaking blood vessels that grow under the retina and cause the macula to bulge or lift up in the eye, ultimately damaging it and distorting vision. This treatment works best when the leaky blood vessels have not grown under the macula and are located away from the central part of the macula on which the visual image is focused. Because heat from the laser beam destroys tissue surrounding the site of the beam's contact with the blood vessels, healthy tissue can be lost in the procedure, producing blind spots in vision. To treat leaky blood vessels under the macula with the laser beam would damage the macula as much as the leaky blood vessels themselves. As a result, only a small percentage of patients with wet AMD are eligible for laser surgery, and it is not often performed, according to the National Eye Institute. Early detection of wet AMD before it nears the central part of the macula is important in determining whether it can be treated.
The FDA has approved two drugs for the treatment of wet AMD that can be injected directly into the eye (called anti-VEGF therapy)—ranibizumab (Lucentis) and pegaptanib sodium (Macugen). In people with wet AMD, abnormally high levels of a certain protein promote the growth of abnormal blood vessels; both drugs target this protein, thus inhibiting the growth of new vessels and the progression of AMD. Ranibizumab, a form of the colorectal cancer drug Avastin and approved for treatment of AMD in 2006, requires monthly injections in the eye. Pegaptanib sodium, approved in 2004, requires injections every six weeks. Potential complications associated with these injected drugs include inflammation within the eye and retinal detachment. Bevacizumab (Avastin) works similarly to ranibizumab but it is only FDA-approved for treatment of colorectal cancer; some health care providers prescribe it off-label to treat macular degeneration because it is less expensive than ranibizumab.
Verteporfin (Visudyne) was the first drug therapy approved by the FDA for treatment of wet AMD, but newer drugs have largely replaced its use. Visudyne is used in photodynamic therapy, in which the light-activated drug is administered intravenously in the patient's arm. Then, a low-powered laser beam is shined into the eye to stimulate the drug, starting a chemical process that destroys the leaky blood vessels. Like laser surgery, the photodynamic laser therapy cannot restore lost vision. Verteporfin causes sensitivity to light for five days after treatment, as well as other side effects.
Because dry AMD can sometimes progress to wet AMD, regular eye examinations are important. Additionally, there are many types of low-vision devices designed to help you make the most of your sight, such as special high-magnifying eyeglasses and electronic screens that display text in an enlarged form. Your health care professional can prescribe such aids for you or may refer you to a low-vision specialist. Vision rehabilitation instructors can help you learn new ways to perform daily living tasks, such as:
- marking clothes, groceries and medications so they are easily recognizable
- improving lighting and reducing glare
- modifying the home so it is safe and comfortable
Orientation and mobility instructors can teach you how to move around indoors and outdoors when you have low vision. Various adaptive devices, such as clocks and telephones with large numbers, and large-print books, can help those with low vision manage better by themselves.
Prevention
There is no known way to prevent age-related macular degeneration (AMD), although the vitamin/mineral combination described earlier (high doses of vitamins C, E, beta carotene and zinc—along with copper) can slow progress of intermediate or early advanced AMD.
Your best bet for protecting your eyesight is getting regular, comprehensive eye examinations. If you are diagnosed with dry AMD, the National Eye Institute recommends a dilated pupil eye exam at least once a year. And, because dry AMD can progress to wet AMD, if you have dry AMD, you might want to discuss with your health care professional whether you should use an Amsler grid to check each eye regularly for signs of wet AMD. If you detect changes, contact your health care professional for an eye exam.
If you are diagnosed with wet AMD and your health care professional recommends laser surgery or photodynamic therapy, don't delay the procedure. If you do, the disease may progress to the point where treatment to try to slow its progression and protect remaining sight may not be an option. Ask your health care professional which other steps you should take to evaluate and preserve your vision, particularly in the arena of vitamin/mineral supplements and omega-3 fatty acids.
Your lifestyle can play a role in reducing your risk of developing AMD:
- Eat a healthy diet high in green, leafy vegetables and fish.
- Do not smoke.
- Maintain normal blood pressure.
- Watch your weight.
- Exercise regularly.
- Maintain healthy cholesterol levels.
Facts to Know
- Macular degeneration is the leading cause of severe vision loss among people age 60 and older, according to the National Eye Institute.
- According to the American Macular Degeneration Foundation, macular degeneration affects more than 10 million Americans.
- The greatest risk factor for macular degeneration is being age 60 or older.
- Women are at slightly greater risk than are men for developing macular degeneration, according to the National Eye Institute.
- According to the National Eye Institute, although only about 10 to 15 percent of people with macular degeneration have the wet form of the disease, it causes significantly more severe vision loss from the disease than the dry form.
- More than 85 percent of people who have macular degeneration have the dry form of the disease, which has no effective treatment.
- Only a small percentage of wet macular degeneration patients are candidates for laser surgery because the spreading abnormal blood vessels have advanced too close to the part of the macula on which visual images are focused, according to the National Eye Institute. Photodynamic therapy with verteporfin (a medication) treatment may be an option for patients in whom the abnormal blood vessels extend underneath the central macula or fovea.
- Macular degeneration is the leading cause of adult vision loss in industrialized countries. Although central vision can be severely affected or lost, peripheral vision remains.
- The Age-Related Eye Diseases Study, sponsored by the National Eye Institute, found that antioxidant supplements, combined with zinc and copper, can reduce the risk of intermediate or early advanced AMD progressing to advanced AMD by 25 percent.
- Macular degeneration has no cure.
Questions to Ask
Review the following Questions to Ask about macular degeneration so you're prepared to discuss this important health issue with your health care professional.
- Am I at risk for developing macular degeneration?
- What is my visual acuity or central vision?
- What is my peripheral vision field?
- Am I likely to lose more vision?
- What kind of macular degeneration do I have?
- Are there certain vitamins or minerals I should take?
- Can laser surgery help me?
- How can I best monitor the progression of my disease?
- Are there any low-vision aids or adaptive devices I can use to help me better use the vision I have? What are they?
- Could I benefit from an evaluation by a low-vision specialist?
- What training should I get to make sure I can move around safely and perform my daily activities?
Key Q&A
I've been diagnosed with macular degeneration. Will I go blind?
No. Peripheral, or side, vision usually is not affected by macular degeneration, and people rarely go completely blind from the disease. Macular degeneration involves destruction of the macula, the central part of the eye's retina that allows you to see fine, sharp details straight ahead. The retina is made of light-sensitive tissue that sends visual messages via nerve impulses to the brain through the optic nerve. The brain then processes the nerve signals into a "picture" that you see. The macula consists of millions of light-sensitive cells that help provide the central vision used in reading, driving, recognizing faces and doing close work, such as sewing. As the macula deteriorates, central vision becomes blurred and distorted. There also is loss of fine detail, difficulty reading, a greater need for more light to see and reduced color vision. Supplementing with antioxidant vitamins, zinc and copper may slow the disease's progression.
What is age-related macular degeneration, or AMD?
Macular degeneration often is called age-related macular degeneration, or AMD, because the greatest risk factor for the disease is advanced age. Although AMD can occur during middle age, according to the National Eye Institute, people age 60 and older have the greatest risk. The National Eye Institute reports that results from a large study found that middle-aged people have a 2 percent risk of developing AMD, but in people over age 75, that risk increases to 30 percent.
What's the difference between dry AMD and wet AMD?
Dry AMD occurs when the light-sensitive cells in the macula slowly degenerate, resulting in a gradual loss of central vision. According to the National Eye Institute, more than 85 percent of people who have macular degeneration have the dry form, also called atrophic macular degeneration. A common early symptom of dry AMD is blurred vision. As cells in the macula deteriorate, fewer details can be seen clearly when looking straight ahead. Often, the blurring disappears in bright light. As the light-sensitive cells die, a small blind spot appears in the middle of the vision field. Over many years, the blind spot increases. Although researchers continue to study the disease, the exact cause of dry AMD is unknown, and there is no cure.
Wet AMD occurs when abnormal, leaky blood vessels develop in or under the retina. The weak blood vessels may leak fluid and bleed, causing the macula to bulge or lift up in the eye, damaging it and distorting vision. This produces the classic early symptom of straight lines that appear wavy. Wet macular degeneration may also cause a small blind spot. Central vision can be destroyed in a short time or after a bit longer period, ranging from a few months to a few years. In some cases, wet AMD can be treated to slow its progression and help preserve central sight. According to the National Eye Institute, the wet type of AMD occurs only in about 10 to 15 percent of people with macular degeneration but accounts for significantly more severe vision loss from AMD than the dry form.
My health care professional recommends that I have laser surgery for wet AMD. Should I schedule the surgery now, or wait a couple years and see how bad my vision gets?
Because the abnormal blood vessel growth in wet AMD can cause severe vision loss in a short time—anywhere from a few months to a few years—treating the blood vessels at an early stage is more effective. Laser surgery is most effective when the leaky blood vessels growing in or under the retina are caught before they have advanced too close to the part of the macula on which visual images are focused. Only a small percentage of wet AMD patients are candidates for laser surgery because the blood vessels are too close to the macula, and treating with the laser beam would damage the macula even more. It's important to recognize that even with treatment, there is no cure for wet AMD, and whatever vision is lost from the disease cannot be returned. At best, the laser treatment can slow progression of the disease and help maintain what central vision remains. Like dry AMD, wet AMD has no cure.
I have dry AMD. What treatment options do I have?
Currently, there is no treatment that will cure dry AMD. There are, however, many types of low-vision devices designed to help you make the most of your sight, such as special high-magnifying eyeglasses and electronic screens that display text in an enlarged form. Your health care professional can prescribe such aids for you or may refer you to a low-vision specialist. Additionally, vision rehabilitation instructors can help you learn new ways to perform daily tasks, such as marking clothes, groceries and medications so they are easily recognizable; improving lighting and reducing glare; and modifying the home so it is safe and comfortable. Orientation and mobility instructors can teach you how to move around indoors and outdoors when you have low vision. Various adaptive devices, such as clocks and telephones with large numbers, and large-print books, can help those with low vision. Talk to your health care professional about what kinds of low-vision services and training would be best for you. Taking certain vitamins and minerals can also help. For more details on what you can take, see question 6 below.
I've heard people with macular degeneration should take special vitamins and supplements. Do they really work?
Yes. The Age-Related Eye Disease Study (AREDS), sponsored by the National Eye Institute, followed 3,640 participants who had at least early AMD for at least five years. Those at high risk for developing advanced AMD—those with intermediate AMD and with advanced AMD in one eye only—reduced their risk of developing advanced stages of AMD about 25 percent when they took daily antioxidant/mineral supplements containing 500 mg vitamin C, 400 IU vitamin E, 15 mg beta-carotene, 80 mg zinc (as zinc oxide) and 2 mg copper (as cupric oxide).
How can I prevent macular degeneration?
Currently, there is no proven way to prevent macular degeneration. If you are age 60 and older, you are at risk for age-related macular degeneration and should have regular, comprehensive eye examinations at least every two years. If you are diagnosed with dry AMD, the National Eye Institute recommends an eye exam through dilated pupils at least once a year. And, because dry AMD can progress to wet AMD, you should obtain an Amsler grid from your health care professional and use it to check each eye every day for signs of wet AMD. If you detect any vision changes, contact your health care professional for an eye exam. Patients with wet AMD should have eye exams as recommended by their health care professionals. As soon as you are diagnosed, talk with your ophthalmologist about if and when you should begin taking antioxidant vitamins and minerals to help prevent further progression.
Organizations and Support
Organizations and Support
For information and support on coping with Macular Degeneration, please see the recommended organizations and books listed below.
American Academy of Ophthalmology
Website: https://www.aao.org
Address: P.O. Box 7424
San Francisco, CA 94120
Phone: 415-561-8500
Email: customer_service@aao.org
American Council of the Blind
Website: https://www.acb.org
Address: 1155 15th St., NW, Suite 1004
Washington, DC 20005
Hotline: 1-800-424-8666
Phone: 202-467-5081
American Foundation for the Blind
Website: https://www.afb.org
Address: 11 Pennslyvania Plaza, Suite 300
New York, NY 10001
Hotline: 1-800-AFB-LINE (1-800-232-5463)
Phone: 212-502-7600
Email: afbinfo@afb.net
American Health Assistance Foundation
Website: https://www.ahaf.org
Address: 22512 Gateway Center Drive
Clarksburg, MD 20871
Hotline: 1-800-437-AHAF (2423)
National Eye Health Education Program
Website: https://www.nei.nih.gov/nehep
Address: National Eye Institute Information Office
31 Center Drive MSC 2510
Bethesda, MD 20892
Phone: 301-496-5248
Email: 2020@nei.nih.gov
National Library Service for the Blind and Physically Handicapped (NLS)
Website: https://www.loc.gov/nls
Address: Library of Congress
1291 Taylor Street, NW
Washington, DC 20011
Hotline: 1-888-NLS-READ (1-888-657-7323)
Phone: 202-707-5100
Email: nls@loc.gov
Prevent Blindness America
Website: https://www.preventblindness.org
Address: 211 West Wacker Drive, Suite 1700
Chicago, IL 60606
Hotline: 1-800-331-2020
Schepens Eye Research Institute
Website: https://www.schepens.harvard.edu
Address: 20 Staniford Street
Boston, MA 02114
Phone: 617-912-2569
Books
Macular Degeneration: The Complete Guide to Saving and Maximizing Your Sight
by Lylas G. Mogk and Marja Mogk
Macular Degeneration: The Latest Scientific Discoveries and Treatments for Preserving Your Sight
by Robert D'Amato M.D. Ph.D., Joan Snyder, and M.D., Ph.D.
Overcoming Macular Degeneration: A Guide to Seeing Beyond the Clouds
by Yale Solomon
