What are the types of age-related macular degeneration?
There are two forms of AMD: dry and wet. It is possible for a person to suffer from both forms and for the disease to progress slowly or rapidly.
Dry macular degeneration
This is the most common type of AMD. This form, in which the photosensitive cells of the macula slowly break down, is diagnosed in 85 to 90 percent of cases. Yellow deposits called drusen (waste products from metabolism) form and accumulate under the retina, between the retinal pigmented epithelium (RPE) layer and the Bruch's membrane, the blood-retina barrier which supports the retina. Drusen are often found in the eyes of older people, but an increase in the size and number of these deposits is frequently the first sign of macular degeneration. Over time, drusen are associated with deterioration of the macula and the death of RPE and photoreceptor cells, resulting in blurring or a spotty loss of clear, straight-ahead vision. Dry AMD may advance and cause loss of vision without turning into the wet form of the disease. It is also possible for early-stage dry AMD to change into the wet form of the disease
Wet macular degeneration
This is usually preceded by the dry form of the disease. This wet form occurs when the Bruch’s membrane begins to break down, usually near drusen deposits, and new blood vessels grow. This growth is called neovascularization. These vessels are very fragile and can leak fluid and blood, resulting in scarring of the macula and the potential for rapid, severe damage.
The neovascularization disturbs the natural organization of the light-detecting photoreceptor cells and their associated RPE cells, eventually leading to their death. Straight-ahead vision can become distorted or be lost entirely in a short period of time, sometimes within days or weeks. The wet form accounts for approximately 10 percent of all cases of AMD, but it results in 90 percent of the cases of legal blindness. All wet AMD is considered advanced.
Can you get AMD in only one eye, or does it always occur in both?
It is possible to develop AMD in only one eye. However, as the disease progresses both eyes may become affected. If an individual has macular degeneration in one eye, he or she is more likely to develop it in the other eye than someone who does not.
What potential vision-related symptoms should I be aware of and mention to my eye doctor if they arise?
- More light is needed for tasks such as reading
- A blurry spot appears in the center of the visual field
- A blurry spot becomes larger and darker
- Straight lines may appear wavy
- Straight-ahead vision becomes distorted or lost entirely in a short period of time
Do not delay in informing your doctor of any changes in your vision, as they may be indicators of potential permanent damage that can happen very quickly
If diagnosed with AMD, what questions should I ask my doctor?
- Do I have wet macular degeneration or dry?
- Do I have it in one eye or both eyes?
- What stage of the disease do I have?
- How often should I come in for check-ups?
- What is the Amsler grid and how often should I perform a test with it at home?
- Are there things that I can do to delay disease progression?
- What are the current treatments for macular degeneration?
- Are there lifestyle changes that I should make?
- Should I alter my diet?
- Do my current medications affect disease progression?
- Should I begin to take vitamin supplements?
- Will vitamin supplementation interfere with medications, or vice versa?
- Are there any experimental treatments for macular degeneration?
Although there is no cure, are there treatments available for AMD?
For the wet form of the disease, some common treatments that can help control the abnormal blood vessel growth and bleeding in the macula for those with wet macular degeneration include injections, laser surgery, and photodynamic therapy. The injectable medications, such as Avastin, EYLEA® (aflibercept), Lucentis® (ranibizumab) and Macugen® (pegaptanib sodium), stabilize or effectively reduce damage from wet AMD.
The safety and effectiveness of EYLEA was evaluated in two clinical trials involving 2,412 adult patients. People in the study received either EYLEA or Lucentis (ranibizumab injection). The primary endpoint in each study was a patient’s clearness of vision (visual acuity) after one year of treatment. In comparison to Lucentis, all EYLEA treatment groups had a similar, consistent mean improvement in visual acuity (lost no more than 15 letters or 3 lines on a vision chart), and a similar, generally favorable safety profile. Importantly, EYLEA dosed 2 mg every two months was demonstrated similar in efficacy and safety to Lucentis dosed monthly.
The efficacy of Lucentis depends on a number of factors and is different for every patient. However, in a clinical trial where 800 patients were treated over two years, 90 percent of patients saw their vision stabilize, while 40 percent saw their vision improve (gained up to three lines on a vision chart). The definition of "stabilization of vision" here does allow for some vision loss (accountable to age, testing conditions, and other factors), where patients could lose up to 15 letters on the vision chart (or three lines).
Physicians have also used Avastin® (bevacizumab injection) as an “off-label” treatment for wet macular degeneration, and several other prospective treatments are in various stages of development.
The National Eye Institute (NEI) of the U.S. National Institutes of Health conducted clinical trials (called Comparison of AMD Treatments Trials or CATT) to study the relative efficacy and safety of Avastin and Lucentis. In May 2011, halfway through CATT, it was reported that Avastin and Lucentis were found to be nearly equally effective in treating AMD.
In April 2012, CATT findings showed that the best results for maintaining visual acuity are achieved with injections every four weeks, with comparable results for either Avastin or Lucentis. The report showed that receiving doses of either drug “as needed” was less effective for maintaining visual acuity than with regular monthly dosing.
Although Avastin was associated in the CATT trial with a greater number of serious adverse events than Lucentis, the researchers could not determine whether these differences were due to statistical chance or to real differences between the safety profiles of the two drugs.
A parallel four-year study (called IVAN) conducted in 23 United Kingdom hospitals and universities also found the two drugs equally effective in treating wet AMD and found no difference in the ability of participants to read small print. In results reported in May 2012, IVAN did find a slightly higher incidence of heart problems among the patients who took Lucentis, but when the results of the IVAN and CATT studies were combined, this statistical difference disappeared.
Results from ongoing clinical trials worldwide may provide more information about the risks of taking Avastin relative to Lucentis for wet AMD.
For dry AMD, there are currently no specific treatments. However, in some cases it may be possible to delay or prevent the progression of AMD from the intermediate to the advanced stage, where vision loss occurs. The National Eye Institute’s Age-Related Eye Disease Study (AREDS and the follow-up AREDS2 trial) found that taking nutritional supplements with a specific high-dose formulation of certain antioxidants and minerals delayed or prevented the progression of AMD from the intermediate to the advanced stage by about 25 percent.
In the AREDS2 trial, scientists found that the antioxidants lutein and zeaxanthin proved safer than the beta-carotene used in the original AREDS study. Betacarotene increases the risk of lung cancer for smokers or ex-smokers. AREDS2 also found that the addition of omega-3 fatty acids to the special formula did not improve the formula’s success: hence that well-known antioxidant is not in the AREDS2 formula.
The AREDS2 formula includes:
- 500 milligrams of vitamin C
- 400 international units of vitamin E
- 10 milligrams of lutein
- 2 milligrams of zeaxanthin
- 80 milligrams of zinc as zinc oxide, and
- 2 milligrams of copper as cupric oxide. (Copper was added to prevent copper-deficiency anemia that can happen in people who take high levels of zinc.)
Patient Recommendations for AREDS
The high dosages of antioxidant vitamins and zinc recommended in the final AREDS2 formula cannot be provided through an ordinary diet or multivitamin.
The AREDS formulation does not restore lost vision and is not a cure for AMD, but rather a dietary supplement that may benefit those whose disease is at high risk of progressing to advanced stages of AMD (see table). The AREDS formula did not show any benefit to those with early stage AMD.
Scientists will follow up for at least five years.
Always talk to your doctor before you take any formulation, and be sure to review all your current supplements with your doctor before you begin.
Who Could Take the AREDS2 Formula?
(On mobile devices, swipe left to see all of the table columns.)
|Stages of AMD||Recommendation|
|Early AMD||Taking the AREDS2 formula is not proven to have any effect on those with early stage AMD. Visiting the doctor regularly is the best way to monitor whether the disease is progressing.|
|Intermediate AMD||Those with intermediate AMD in one or both eyes could take the AREDS2 formula as it may slow vision loss and development of advanced AMD.|
|Advanced AMD||If a patient has advanced AMD, whether wet or dry in only one eye, the AREDS2 formula is recommended.|
What is an Amsler grid?
To discover any changes to your vision as early as possible, your eye care professional will probably have you test your own vision on a regular schedule using a small, hand-held Amsler grid. He or she may also do this at the office. At home, you will hold the chart at reading distance in good light, cover one eye, and focus on a black dot in the middle of the grid, then repeat with the other eye. If the lines of the grid appear dim, irregular, wavy, or fuzzy, you should schedule an eye exam immediately.
You can download an Amsler grid here or call 1-800-437-2423 to request one.
What resources are available to help people with AMD and their caregivers?
There are a great many resources available to people with low vision and their caregivers. For instance, every state has an agency on aging. You may find it in the phone book, online, or with the help of a librarian or friend. Professional lowvision therapists at eye clinics or other organizations can assist you. Let your eye doctor know what kind of limitations you are experiencing due to vision loss. He or she can then refer you to a vision rehabilitation center, where a low-vision therapist can work with you to help you adapt and resolve specific problems.
You can also modify your environment, use low-vision aids, develop your senses of hearing and touch, and practice using peripheral vision. Your doctor can prescribe optical devices such as magnifiers. Many non-prescription magnifying glasses and devices are also available to assist with reading and other close work, such as sewing or model-building. These devices range from the simple and inexpensive to more expensive high-tech products that can aid in using computers and watching television.
Many styles of magnifiers, including discreet ones, can be found at drug and medical supply stores, or may be ordered online or by phone through low-vision product catalogs. A hand-held magnifying glass can help with reading medicine bottle labels, mail, price tags in stores, and restaurant menus. Other magnifiers come in the form of eyeglasses or clip onto glasses to free your hands for other activities.
Commonly used household items with large numbers and letters, and others that “talk,” are also available. There are many sources for large-print books and audio materials, as well as services that read newspapers and magazines by phone or over the radio.
Electronic reading aids are proliferating, such as: computer programs that magnify the computer screen and/or read screen text out loud; special scanners to carry while shopping that read out prices, sizes, and colors; web browser plugins; and smartphone applications. One specialized device can take pictures of signs or menus and read the words in the pictures aloud.
Where can I find more information?
- The macular degeneration section of our website goes into greater depth on many of the above topics and covers additional areas of concern, both medical and social. You can learn where to get help and access to resources, as well as download free BrightFocus publications. And explore our Ask an Expert section where you can read or post queries to doctors.
- See a list of helpful organizations dealing with the topics listed above.
This content was last updated on: March 1, 2018
The information provided is a public service of the BrightFocus Foundation and is not intended to constitute medical advice. It should not in any way substitute for the advice of a qualified healthcare professional. Please consult your physician for personalized medical advice; all medications and supplements should only be taken under medical supervision. BrightFocus Foundation does not endorse any medical product or therapy.