Macular degeneration often starts with the appearance of drusen, yellowish-white deposits beneath the retina caused by the buildup of retinal waste products. The drusen themselves usually do not affect vision and are frequently found with aging (similar to age spots on the skin). However, if drusen are numerous and appear in the center of the macula, they can lead to progressive deterioration, including the development of severe macular degeneration. The main types of AMD are:
The most common type of macular degeneration is associated with the aging process and is called "dry" macular degeneration. This form accounts for the overwhelming majority of cases (about 80 percent) and is caused by a breakdown or thinning (atrophy) of the tissues in the macula. This leads to a loss of vision cells in the macula, which can make objects appear washed out or difficult to see. Fortunately, most "dry" cases are not associated with severe visual loss.
About 10 percent of AMD falls into a category called "wet" macular degeneration. It is marked by the growth of new abnormal blood vessels under the macula, which can leak fluid and blood. This leakage may create scar tissue, resulting in a blind spot that causes a rapid and profound loss of sharp central vision. "Wet" macular degeneration is more rare than other forms but, of all patients legally blind from AMD, the vast majority have this type. The earlier it is detected, the better the chances for preserving vision.
Less common reasons for damage to the macula include injury, infection, inflammation, marked nearsightedness, hereditary factors and drug toxicity.
Since images outside of the blurred area are often still visible, macular degeneration may result in legal (less than 20/200 vision), but not total blindness. People are usually able to perform most of their daily activities and take care of themselves by using their remaining side (or "peripheral") vision.
Researchers are not certain what causes the changes in the macula that lead to AMD. Aging and heredity are the main culprits. Known risk factors include:
Macular degeneration usually develops gradually and painlessly. It can cause different symptoms in different people. If only one eye is affected, the disease may be difficult to detect in its early stages. Good vision in one eye can often mask visual difficulty in the other eye. As the condition progresses, however, a number of symptoms may become more obvious, including:
If you suddenly notice any of these symptoms, you should see an eye care specialist as soon as possible. Do not assume you simply need a new pair of glasses and then wait to make an appointment for the future.
You can test for early warning signs of macular degeneration with a simple, inexpensive and effective screening tool called the Amsler Grid. A normal, healthy eye sees the grid pattern (shown below) in its entirety, without distortion. An eye with macular degeneration, however, may see the lines as distorted or bowing toward the center, or may have a shadowy spot at the point of focus or entire areas that are missing.
People diagnosed with macular degeneration should do this test daily or at least several times a week. This is especially important for detecting and treating cases where the dry type of macular degeneration changes into the more severe wet type.
If you notice any problems or changes, contact your eye care specialist immediately.
A complete eye examination is necessary to evaluate the presence, type and severity of AMD and to determine whether treatment would be beneficial. At Eye Care Specialists, the following instruments and tests may be used.
Ophthalmoscope: This instrument allows us to check the health of your optic nerve and retina for any abnormal conditions, such as AMD or retinal detachment.
Slit Lamp: With this special microscope, we can see inside your eye to evaluate its overall health. In addition, by using a special lens with the slit lamp, we are able to conduct a detailed examination of the macula.
Amsler Grid test: This self-test (see above) helps to detect subtle and early changes in your vision that may be caused by AMD.
OCT Scan: A fast, non-invasive and painless scanning test (similar in concept to a CT scan of the inside of the eye) that enables us to determine how and when to treat wet AMD by mapping areas of fluid shrinkage and drying.
Fluorescein Angiogram: This in-office test involves injecting a fluorescein dye into the arm. Once the dye reaches the blood vessels inside the eye, a special camera takes a rapid series of pictures (not x-rays). The retina is the only part of the body where blood vessels can be seen directly. Because any new or abnormal retinal vessels leak the dye, fluorescein pictures can be used not only for the diagnosis and classification of AMD, but as a "roadmap" for treating leaky vessels with the laser.
Currently, treatment for this more common type of AMD primarily involves measures to prevent or slow its progression. For example, the intake of vitamins (see below) and omega fatty acids and the avoidance of risk factors (most importantly, not smoking) have proven beneficial in numerous studies. Because dry AMD usually does not result in rapid vision loss, many patients retain good sight throughout their lives. Some people, however, experience a significant loss of central vision over time. These patients usually benefit from magnifiers and other low vision aids.
Some patients with this rarer type of AMD may benefit from treatment. At present, there are three FDA-approved treatments for neovascular ("new vessel" or "wet") AMD: photodynamic therapy (PDT) with a drug called Visudyne™ (a laser light-activated dye), injection into the eye of a drug called Macugen™, and injection into the eye of a drug called Lucentis™. Although PDT and Macugen have proven to slow down the rate of visual loss, most people do not get back better vision. Besides these FDA-approved medications, many ophthalmologists use other drugs that are not specifically approved for AMD treatment, but which have shown some benefit. The two medications used this way are intravitreal Kenalog™ (a long-acting cortisone-like drug) and Avastin™ (a drug similar to Lucentis that was originally created to treat metastatic colorectal cancer).
What are the possible benefits of Lucentis™ & Avastin™?
Both (which are made by the same company) have been shown to not only slow or stop the progression of wet AMD, but to significantly reverse deterioration and improve vision. In fact, the FDA approved Lucentis based on results from two pivotal clinical trials. In the MARINA trial, after 24 months, 33 percent of Lucentis-treated patients experienced a clinically significant improvement in vision, compared with only five percent of untreated patients. (Improvement was defined as gaining the ability to read 15 or more letters than before on an eye chart.) In the ANCHOR trial, after 12 months, 40 percent of Lucentis-treated patients experienced a clinically significant improvement in vision, compared with six percent of verteporfin PDT-treated patients. In both studies, almost all Lucentis-treated patients (approximately 95 percent) maintained their visual acuity (clarity or sharpness of vision), compared with 62-64 percent of control-treated patients.
How do these drugs work?
They inhibit the growth of the abnormal blood vessels that cause AMD as well as treat the swelling of the macula due to AMD. The goal of treatment is to prevent further loss of vision. Although some patients have regained vision, there are no guarantees that Lucentis or Avastin will restore lost vision or prevent further loss.
How are the drugs given?
Once numbing drops take effect, a painless injection is made directly into the vitreous (jelly-like substance inside the eye). The patient is then free to resume activities.
How often do you need injections?
To achieve the best possible benefit, they must be administered approximately monthly. Your eye care specialist will evaluate your response and determine how often you will receive the injection and for how long.
Are there any risks or side effects?
Prior to treatment, potential risks and benefits are reviewed by the doctor and described in detail in an Informed Consent form.
Research is being conducted into transplantation of embryonic cells and implantation of tiny telescopes or bionic cameras. It is hoped that in 10-25 years, these or other treatments will effectively help all AMD patients.
A National Eye Institute Age-Related Eye Disease Study (AREDS) has found that high levels of antioxidants and zinc can reduce the risk of developing advanced AMD by about 25 percent and the risk of related vision loss by about 19 percent. Although these nutrients cannot cure AMD or restore sight, study results suggest they may be key to protecting and preserving existing vision for patients with either wet or dry degeneration.
Who should take these nutrients?
People diagnosed as being at risk for advanced macular degeneration should strongly consider a supplement that matches the AREDS dosage. Although it currently has not been documented, it may also be helpful for patients with mild or moderate AMD to take lower dose supplements, like "Ocuvite with Lutein." Upon careful dilated examination, your eye doctor can let you know which, if any, of these applies to you.
What dosages were used in the study?
|Vitamin C||500 mg|
|Vitamin E||400 International Units|
|Zinc||80 mg as zinc oxide|
|Copper*||2 mg as cupric oxide|
*Copper was added to the formulation to prevent copper deficiency, which may be associated with high levels of zinc supplementation.
Where can I find this supplement?
Bausch & Lomb, an eye care company, provided the AREDS formulation. They market it as a tablet called "Ocuvite PreserVision" through pharmacies and retail outlets. Other companies sell similar formulations. Antioxidant vitamins and zinc can also be purchased separately; however, to avoid any overdosing or copper deficiency, check with your doctor before using.
What if I already take a multivitamin?
Multivitamins and/or diet alone can't achieve the high levels of nutrients in the study.
Most AREDS participants took both a multivitamin and the supplement.
What are the potential side effects?
The 4,757 AREDS participants aged 55-80 reported few side effects. About 7.5 percent of those assigned to zinc treatments (compared with five percent who weren't given zinc) experienced urinary tract problems that required hospitalization, including infections, kidney stones, incontinence and enlarged prostate. Zinc-takers also reported more anemia; however, testing showed no difference between groups. Yellowing of the skin, a known side effect of large doses of beta-carotene, was also sometimes reported.
Should I be cautious about using these nutrients and doses?
Yes. Many people, especially older adults, use a variety of prescription medications, over-the-counter drugs, dietary supplements and herbal medicines. High-dose vitamins and minerals like the AREDS formulation can interfere with these medications or decrease the absorption of other nutrients in the body—ultimately affecting a person's nutritional and health status.
For example, beta-carotene has been shown in two National Cancer Institute studies to significantly increase the risk of lung cancer in smokers. As a result, smokers should check with their doctor before taking the AREDS formulation. Also, high doses of zinc may cause copper deficiency and, therefore, need to be balanced with increased copper intake. Generally, any self-medication with high doses of vitamins and minerals is not recommended, especially for people with cancer, diabetes and heart disease.
If you plan to take eye-related nutrients, discuss it (and whatever else you take) with your doctor, eye care specialist and/or pharmacist to determine which formulation and dosages are best for you.
The following measures may help you to "see" life to the fullest:
Losing sight to AMD does not inevitably mean losing your way of life. By using their remaining side vision, along with a variety of coping techniques and tools, most people are able to lead independent, productive lives pursuing their goals and interests. The key is to reach out and take advantage of the many resources that are available, including the support of friends and family.
Our office can suggest where to obtain special lamps, magnifiers, eyeglasses, large-print publications and other aids. We also have access to a new, lighted magnifying device that can plug into your TV to enlarge words on a medicine bottle, magazine pages, or anything else you wish to show on your screen.
We also strongly urge you to contact the following organizations for counseling; needs assessment; low vision aids; and help with obtaining Social Security/veterans benefits, income tax exemptions, and handicapped parking designations or transportation services. Some groups even offer in-home visits to show you ways to make tasks easier and safer.
The most satisfied patients are those who are educated, active partners in their own care. As such, we encourage you to ask questions and stay abreast of new developments that may improve or protect your vision. And, we remind you that keeping your eye appointments is essential to ensuring that you have every opportunity to see life to the fullest.
Badger Association for the Blind & Visually Impaired
912 N. Hawley Rd.
Milwaukee, WI 53213
(Offers information, products, local resources, etc.)
Prevent Blindness Wisconsin (an affiliate of Prevent Blindness America)
759 N. Milwaukee St.
Milwaukee, WI 53202
(Offers information, event listings, program and service listings, etc.)
State of Wisconsin Office for the Blind & Visually Impaired
(In addition to making home visits, this organization sets up local support groups)
AMD Alliance International
(Offers information, caregiver tips, resources, etc.)
American Foundation for the Blind
15 West 16th St.
New York, NY 10011
(Offers information, adaptation tips, books and guides)
The National Eye Institute
(Offers information, AREDS nutrition study Q&As, research news, etc.)
Since 1985, Eye Care Specialists has provided comprehensive medical, surgical and laser care for virtually every eye condition to more than 121,000 people in southeastern Wisconsin. If you would like detailed booklets/handouts on the information contained in this section or other eye-related topics, please contact our Communications & Education Department at 414-321-7035. To schedule a comprehensive eye evaluation, call one of our three convenient Milwaukee-area locations shown at the top of this web page.