Macular Degeneration
All physicians at EyeHealth Northwest are trained to diagnose and care for patients with Macular Degeneration. In addition, we also have a fellowship trained vitreoretinal specialist on our staff, Dr. Jonathan Yoken and Dr. Brian T. Chan-Kai, Fellowship trained Retinal Specialists are available for Macular Degeneration disease treatments, surgery and consultations.
The macula is a specific area of the retina. It is at the center of the visual field—when looking directly at an object, you are seeing it with the macula, while the rest of the retina provides peripheral vision. Although it represents only a small fraction of the total size of the retina—about the size of the capital letter “O” on this page—the macula is crucial for visually demanding tasks like reading, driving a car, and color vision. Diseases of the macula may interfere with “detail vision”, making these activities more difficult. Macular problems can also cause images to appear distorted, or may cause an area of cloudiness or darkness to form at the center of the visual field. Fortunately, many diseases that affect the tiny macula may spare the rest of the retina, thereby preserving peripheral vision. Therefore, diseases such as Age Related Macular Degeneration (ARMD) rarely result in complete loss of sight.
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| "Dry AMD", Drusen |
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| Vision change in "Wet" AMD |
Visual problems in macular degeneration take two basic forms. The first, milder problem occurs as the cells of the macula slowly lose sensitivity and may become less numerous. This may result in fluctuating vision—the sight is clearer on some days than others—and slowly (typically over months to years) vision may worsen. This is referred to as the “dry” form of macular degeneration.
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| "Wet" AMD with new blood vessels in the macula. |
The second type of problem occurs more suddenly and may cause a more serious drop in vision. Tiny clusters of abnormal blood vessels may begin to grow beneath the macula. These vessels “leak” and blood or watery fluid may accumulate beneath the macula. This can result in irreversible damage to the macula, resulting in loss of the central detail vision. The presence of leaks is often referred to as the “wet” form of macular degeneration.
While the most important risk factor for macular degeneration is age, it is not yet understood why macular degeneration occurs in some seniors and not in others.
There may be some inherited factors that predispose individuals to have this condition, and research to identify the genes which are associated with macular degeneration is ongoing. The development of drusen, and the slow loss of retina cells that sometimes occurs, is not preventable by any means yet identified. However if the genetic basis of macular degeneration was identified, it might be possible to correct the defect before macular degeneration can begin. Many researchers are working on this question, but it remains a difficult problem.
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| "Wet" AMD. New blood vessels visible with Fluorescein Angiography. |
If a person has macular degeneration, it appears that keeping the entire body healthy—control of blood pressure, control of cholesterol, good nutrition, and avoiding cigarettes—helps to reduce the risk of developing visual loss. The Age-Related Eye Disease Study (AREDS) was a major study sponsored by the National Eye Institute (NEI). In the study, scientists looked at the effects of zinc and antioxidants (vitamin C, vitamin E & beta carotene i.e. provitamin-A), on patients with cataracts and age-related macular degeneration (AMD). Patients with intermediate to advanced AMD, as determined by the doctor, who were taking the anti-oxidant and zinc combination had a demonstrable decrease in the incidence of developing wet AMD.
While most patients in the study experienced no serious side effects from the doses of zinc and antioxidants used, a few taking zinc alone had urinary tract problems that required hospitalization. Some patients taking large doses of antioxidants experienced some yellowing of the skin. The long-term effects of taking large doses of these supplements are still unknown. Previous studies have shown that individuals who smoke and take beta-carotene are at an even greater risk of developing lung cancer, and therefore current and recent smokers should not take beta-carotene.
If you have intermediate (or advanced macular degeneration in one eye only), talk to your physician about taking nutritional supplements. Your doctor can help you determine if they may be beneficial-and safe-for you, and what types and doses of supplements to take. The doses used in the study were: Vitamin C 500 mg, Vitamin E 400 IU, Beta-carotene 15 mg, Zinc 80 mg, as zinc oxide, Copper 2 mg, as cupric oxide (copper should be taken with zinc, because high-dose zinc is associated with copper deficiency).
The effect of other antioxidants such as Lutein, Zeaxanthin, and Omega-3 fatty acids is not yet known. They are currently being evaluated in a large-scale national study, and results should be known in the near future.
An additional factor that may aggravate macular degeneration is unprotected exposure to the sun’s UV rays. While this is not yet proven, most patients find some form of sunglass use (with UV filtration) makes seeing more comfortable and in some cases, certain tints can enhance contrast sensitivity.
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| Amsler Grid |
Your doctor will schedule regular follow-up appointments to monitor your condition. In addition, we strongly recommend monitoring your vision with an Amsler grid (see below) at least twice a week, so that any changes in vision will be recognized as early as possible. Instructions on how to use the grid will be provided.
Any changes on the Amsler grid—waviness of the lines, blank or missing lines, or blurring of the lines—should be reported to your doctor immediately. Early detection is our best defense against visual loss in macular degeneration!
- waviness or distortion of the grid lines,
- blank or missing lines, or
- blurring of the lines
Additional symptoms include:
- Words on a page look blurred
- A dark or empty area appears in the center of your vision
- Straight lines look distorted.
Early detection through routine vision care with your EyeHealth doctor is our best defense against visual loss and future sight preservation.
Don’t wait until blurred vision is obvious. Macular degeneration can be diagnosed with medical testing & assessments before the serious effects of blurred vision & disease onset are apparent:
- medical eye examination
- vision test with Amsler grid
- viewing the macula with ophthalmoscope by your doctor
- special photographs of the eye: fluorescein angiography to find abnormal blood vessels under the retina.
There is no cure for dry AMD, but vitamin supplementation, as described above, may slow down the progression of the disease. Please check with your doctor to see whether vitamins would be appropriate for your eyes.
"Wet" macular degeneration
Significant advances in treating "Wet" macular degeneration have been the development of a new class of drugs. The drugs are based on the discovery that a group of proteins in the body, one of which is called vascular endothelial growth factor (VEGF), play a significant role in the formation of the abnormal blood vessels that damage the retina in wet macular degeneration.
One drug used to treat wet AMD is Lucentis (ranibizumab). Lucentis blocks VEGF, which in turn causes the abnormal vessels to shrink. In the studies that evaluated Lucentis, the results were more favorable than for any other previously FDA approved treatment. Instead of only slowing the rate of vision loss, the drug appeared to stop disease progression in most people for as long as two years. Also, some patients experienced significant visual improvement. It is important to note that the patients in the study had fairly recently diagnosed macular degeneration that had not yet progressed to scarring.
Another drug, Avastin (bevacizumab) is used as well. Avastin is similar to Lucentis and also blocks VEGF. Based upon the results of clinical trials that demonstrated its safety and effectiveness, Avastin was approved by the Food and Drug Administration (FDA) for the treatment of metastatic colorectal cancer. Blocking or inhibiting VEGF helps prevent further growth of the blood vessels that the cancer needs to continue growing.
Once a device or medication is approved by the FDA, physicians may use it "off-label" for other purposes if they are well-informed about the product, base its use on firm scientific method and sound medical evidence, and maintain records of its use and effects. Ophthalmologists are using Avastin "off-label" to treat AMD and similar conditions. Similar to Lucentis, many patients treated with Avastin had less fluid , more normal-appearing maculas, and improved vision. Avastin is also used, to treat macular edema, or swelling of the macula.
The National Institute of Health is currently conducting a two year trial comparing the effects of Lucentis versus Avastin in the treatment of wet AMD. In April 2011, at the end of the first year, they reported that Avastin is as effective as Lucentis.
In addition, other treatments including laser and newer therapies may be available for “wet” AMD, but whether or not you are a candidate for treatment depends on:
- type & location of the leak
- progression over time
- affect on your vision & macula
Some of the newest treatments finally offer the hope of restoring some lost vision, if treatment is started in the early stages. In most cases vision can at least be stabilized. Feel free to talk with your doctor about treatment options for your AMD.
