We look for signs of early Macular Degeneration by performing a dilated exam. Many of these early macular changes occur without any vision symptoms. Depending on the results of the exam we may recommend additional protective measures such as anti-oxidant vitamins, macular imaging, or home monitoring.
Macular degeneration is a condition that damages the macula, the central part of the retina. The macula is responsible for central vision and the ability to see detail.
When the macula is damaged, the eye loses its ability to see detail, such as small print, facial features or small objects. The damaged parts of the macula often cause scotoma, or localized areas of vision loss. When you look at things with the damaged area, objects may seem to fade or disappear. Straight lines or edges may appear wavy.
There are two types of the disease: dry macular degeneration and wet macular degeneration.
Ninety percent of people who have macular degeneration have the dry form of the condition. In dry macular degeneration, waste products may accumulate in the tissues underneath the macula forming yellowish deposits called drusen. The continued presence of drusen interferes with the blood flow to the retina and, in particular, to the macula. Less blood flow reduces the nourishment to the macula causing its light-sensitive cells to stop working efficiently, or atrophy. You will sometimes hear dry macular degeneration referred to as atrophic macular degeneration. Occasionally, a large area of cells will stop working. This is called geographic atrophy, which produces a distorted or blind spot, also known as a scotoma, in the central area of vision. People who have dry macular degeneration may experience a gradual loss of detail vision.
Though the wet form of macular degeneration affects only 10 percent of people diagnosed with the disease, it accounts for almost 90 percent of the severe vision loss associated with the condition. Dry form patients who have large drusen without clear borders or who have many drusen that run together are at greater risk for developing the wet form of the disease.
With wet macular degeneration, new weak blood vessels may grow in or under the retina causing fluid and blood to leak into the space under the macula. As a result, wet macular degeneration is sometimes called exudative macular degeneration. (An “exudate” is material, such as fluid, which has escaped from blood vessels and has been deposited in tissues.) You may also hear wet macular degeneration described as choroidal neovascularization. The choroid is the area of blood vessels beneath the retina, and neovascularization refers to growth of new blood vessels in tissue. In choroidal neovascularization, blood vessels from the choroid grow into the macula.
Both the dry and wet form of AMD causes no pain. The most common early sign of dry macular degeneration is blurred vision. As fewer cells in the macula are able to function, people will see details less clearly in front of them, such as faces or words in a book. If the loss of these light-sensing cells becomes great, people may see a small — but growing — blind spot in the middle of their vision.
The classic early symptom of wet macular degeneration is that straight lines appear crooked. This occurs when fluid from the leaking blood vessels gathers and lifts the macula, distorting vision. A small blind spot may also appear in wet macular degeneration, resulting in loss of one’s central vision.
Regular eye exams are the key to early detection of macular degeneration since symptoms may or may not be present in people who have the disease. Early drusen can be seen in an eye exam before symptoms develop, so you should visit your eye care professional regularly.
While there are no known causes of macular degeneration, many studies have been performed which illustrate factors that may put you at risk for the disease. There are risk factors you can’t control, such as age and genetics, and risk factors that you can control, such as smoking and poor nutrition.
An unhealthy lifestyle, which may include smoking, poor nutrition or limited exercise, could contribute to your risk of developing macular degeneration. As a result, many risk factors are within your control to reduce your chance of getting the disease and to promote better health.
You can lessen the risk of developing macular degeneration by reducing risk factors within your control, such as smoking and high blood pressure. You are never too young to reduce your risk for disease, so, no matter what your age, you can incorporate the following guidelines into your life.
By following these guidelines, you not only may reduce your risk of developing macular degeneration, but you may also be able to stabilize or slow the effects of vision loss if you have already been diagnosed with the disease.
People under 50 should have an eye exam every three to five years. People with a family history of eye conditions or those with a medical condition associated with eye disease, such as diabetes, should have their eyes tested every year, particularly if they are over 65. If you notice changes in vision — vision becomes blurry, for example — visit your eye doctor immediately.
Once dry AMD reaches the advanced stage, no form of treatment can prevent vision loss. However, treatment can delay and possibly prevent intermediate AMD from progressing to the advanced stage, in which vision loss occurs. The National Eye Institute’s Age-Related Eye Disease Study (AREDS) found that taking a specific high-dose formulation of antioxidants and zinc significantly reduces the risk of advanced AMD and its associated vision loss. Slowing AMD’s progression from the intermediate stage to the advanced stage will save the vision of many people.
The specific daily amounts of antioxidants and zinc used by the study researchers were 500 milligrams of vitamin C, 400 International Units of vitamin E, 15 milligrams of beta-carotene (often labeled as equivalent to 25,000 International Units of vitamin A), 80 milligrams of zinc as zinc oxide, and two milligrams of copper as cupric oxide. Copper was added to the AREDS formulation containing zinc to prevent copper deficiency anemia, a condition associated with high levels of zinc intake.
People who are at high risk for developing advanced AMD should consider taking the formulation. You are at high risk for developing advanced AMD if you have either:
- Intermediate AMD in one or both eyes
- Advanced AMD (dry or wet) in one eye but not the other eye.
Your ophthalmologist can tell you if you have AMD, its stage, and your risk for developing the advanced form. The AREDS formulation is not a cure for AMD. It will not restore vision already lost from the disease. However, it may delay the onset of advanced AMD. It may help people who are at high risk for developing advanced AMD keep their vision.
There is no apparent need for those diagnosed with early stage AMD to take the AREDS formulation. The study did not find that the formulation provided a benefit to those with early stage AMD. If you have early stage AMD, a comprehensive dilated eye exam every year can help determine if the disease is progressing. If early stage AMD progresses to the intermediate stage, discuss taking the formulation with your doctor.
No. The high levels of vitamins and minerals are difficult to achieve from diet alone. However, previous studies have suggested that people who have diets rich in green leafy vegetables have a lower risk of developing AMD.
No. The formulation’s levels of antioxidants and zinc are considerably higher than the amounts in any daily multivitamin. If you are already taking daily multivitamins and your doctor suggests you take the high-dose AREDS formulation, be sure to review all your vitamin supplements with your doctor before you begin. Because multivitamins contain many important vitamins not found in the AREDS formulation, you may want to take a multivitamin along with the AREDS formulation. For example, people with osteoporosis need to be particularly concerned about taking vitamin D, which is not in the AREDS formulation.
There are a number of treatments for wet AMD: laser surgery, photodynamic therapy, and injected medications are most often used. No treatment is a cure for wet AMD. Each treatment may slow the rate of vision decline, stop further vision loss, or even improve the vision in some select cases. The disease and loss of vision may progress despite treatment.
- Laser surgery. This procedure uses a laser to destroy the fragile, leaky blood vessels. A high energy beam of light is aimed directly onto the new blood vessels and destroys them, preventing further loss of vision. However, laser treatment also may destroy some surrounding healthy tissue and some vision. Only a small percentage of people with wet AMD can be treated with laser surgery. Laser surgery is more effective if the leaky blood vessels have developed away from the fovea, the central part of the macula. Laser surgery is performed in a doctor’s office or eye clinic. The risk of new blood vessels developing after laser treatment is high. Repeated treatments may be necessary. In some cases, vision loss may progress despite repeated treatments.
- Photodynamic therapy. A drug called verteporfin is injected into your arm. It travels throughout the body, including the new blood vessels in your eye. The drug tends to “stick” to the surface of new blood vessels. Next, a light is shined into your eye for about 90 seconds. The light activates the drug. The activated drug destroys the new blood vessels and leads to a slower rate of vision decline. Unlike laser surgery, this drug does not destroy surrounding healthy tissue. 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. Photodynamic therapy is relatively painless. It takes about 20 minutes and can be performed in a doctor’s office. Photodynamic therapy slows the rate of vision loss. It does not stop vision loss or restore vision in eyes already damaged by advanced AMD. Treatment results often are temporary. You may need to be treated again.
- Injectable medications. There are a number of medications available that can be injected into the eye to directly treat the abnormal blood vessels that arise in wet macular degeneration. This is usually done through a series of injections spaced apart by weeks or months. The medications work by interrupting the cellular signals that lead to abnormal blood vessel growth in the retina.