Age-Related Macular Degeneration

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Age takes its toll on our eyes just as it does on the rest of the human body. Some symptoms of aging must be accepted gracefully. But other age-related eye diseases can and should be taken seriously. One of these diseases is macular degeneration.

The good news: Right now there are several techniques that may help in treating macular degeneration.

The better news: Studies and research are now being conducted that we hope will one day offer more and better answers in treating this eye disease.

Meanwhile, here’s what you need to know about macular degeneration:

Detecting/Monitoring

Many people may be unaware that they have macular degeneration because they still have good vision. The American Academy of Ophthalmology recommends that, after age 40, people have a routine screening eye examination every two years to check for evidence of glaucoma, cataracts and other age-related eye problems. A dilated fundus examination begins with administering dilating eye drops to open the pupils. This allows the eye doctor to see the retina and look for signs of macular degeneration.

As part of their evaluation, many patients with macular degeneration will undergo a fluorescein angiogram. In this test, fluorescein dye is injected into an arm vein. A special type of camera takes photographs that show the blood vessels in the retina in clear detail. Areas of abnormal blood vessel growth (choroidal neovascularization) can be identified. The presence or absence of abnormal blood vessels is much more clearly demonstrated on the angiogram than during the eye exam. That’s why patients often may require repeat angiograms on return visits.

Amsler grid testing allows patients to monitor their vision at home. One of the first signs of leakage from macular degeneration is that straight lines look bent or distorted. This can be detected by looking at the Amsler grid with one eye at a time. When taking this test, it is important to remember to cover one eye and look at the grid with only one eye at a time. Otherwise, early changes in one eye may be missed. The good eye can compensate for or mask the distortion in the affected eye. If you would like an Amsler grid, please register and provide us with your full name and mailing address and we will send you a magnetic grid. Or you can download the Amsler grid on this screen.

Patients with macular degeneration should get in the habit of checking a grid daily. The earlier abnormal blood vessel growth can be detected, the better the chances are of successful treatment.

Risk Factors

Some people are at greater risk of developing macular degeneration than others. People who are lightly pigmented, with blond hair and blue eyes, have a higher risk. Those with darker pigmentation have a lower risk. Macular degeneration is most common in people of Northern European ancestry and more infrequent among African-Americans.

Family history is a well-documented risk factor for macular degeneration. Someone with a significant family history of macular degeneration in a parent or sibling has twice the risk of developing macular degeneration as the average person of the same age. Therefore, a 65-year-old with an affected parent has a 10-percent risk rather than the five-percent risk of the average 65-year-old.

Several studies have linked smoking to macular degeneration. There are obviously many other reasons to avoid smoking – protecting your lungs and heart. Here’s one more: Quitting smoking may also be beneficial for the eyes. Medical conditions that lead to atherosclerosis (“hardening of the arteries”) have been linked to a higher risk of vision loss from macular degeneration. High blood pressure and high cholesterol have both been associated with an increased risk of age-related macular degeneration (ARMD).

Diet may also be a factor. Some studies have shown that people who eat greater amounts of the “dark green leafy vegetables” – Brussels sprouts, spinach, broccoli and collard greens – have a lower risk of developing macular degeneration. But this has not been definitely proven.

Exposure to ultraviolet light may also be a risk factor, so it’s important to wear sunglasses outdoors on sunny days.

What is Macular Degeneration?

An aging change of the retina, macular degeneration is the leading cause of vision loss in Americans over age 65. The eye is like a camera, with the retina as the “film.” The eye’s optical parts (cornea and lens) focus images of the outside world onto the retina. At the center of the retina is the macula, which provides the sharp vision needed for reading and recognizing faces.

As we get older, some of us develop liver spots and other aging changes on the skin. Likewise, we can develop aging spots on the retina. These aging spots on the retina are called drusen. They become more common as people get older. By age 65, about five percent of us will have evidence of macular degeneration. By age 85, the incidence increases to 20 percent. In addition to drusen, people can also develop pigmented spots and/or atrophic areas in the retina.

There are two types of macular degeneration – dry (atrophic) and wet (exudative). These are not two different conditions, but two different stages of the same condition. Dry ARMD refers to the earlier stage in which drusen and atrophic areas are present. In about 10 percent of ARMD patients, the weak areas lead to abnormal blood vessel growth beneath the retina. These abnormal blood vessels – called choroidal neovascularization (CNV or CNVM) – can bleed or leak. This results in blood and fluid accumulating beneath the retina – and is then referred to as wet macular degeneration.

Dry macular degeneration can sometimes lead to significant vision loss, but milder visual symptoms are more likely. More severe vision loss is usually due to wet macular degeneration. That’s why the wet form is considered a more serious or advanced stage. Still, even with wet macular degeneration, complete vision loss is very, very unlikely. Patients who lose central vision may be unable to drive, read and perform other tasks that require sharp vision. However, they almost always maintain peripheral vision. This usually allows them to walk around without assistance and perform other activities that do not require sharp central vision.

A common misconception is that macular degeneration always results in blindness. That is not true. Many people do suffer significant vision loss from macular degeneration, but many more people with dry macular degeneration have little or no visual trouble.

Treatment Options for Wet AMD

With early diagnosis and proper treatment, you can delay the progression of ARMD. The earlier it is detected, the better your chances of keeping your vision. Wet ARMD typically results in severe vision loss. However, eye care professionals can try different therapies to stop further vision loss. The therapies described below are not a cure. The condition may progress even with treatment.

  • Injections. One option to slow the progression of wet ARMD is to inject drugs into your eye. With wet ARMD, abnormally high levels of vascular endothelial growth factor (VEGF) are secreted in your eyes. This substance promotes the growth of new abnormal blood vessels. The anti-VEGF injection therapy blocks its effects. If you get this treatment, you may need multiple injections. Your eye care professional may give them monthly. Before each injection, your eye care professional will numb your eye and clean it with antiseptics. To prevent the risk of infection, a doctor may prescribe antibiotic drops.
  • Photodynamic therapy. This technique involves laser treatment of select areas of the retina. First, a drug called verteporfin will be injected into a vein in your arm. The drug travels through the blood vessels in your body, including any new, abnormal blood vessels in your eye. Your eye care professional then shines a laser beam into your eye to activate the drug in the blood vessels. Once activated, the drug destroys the new blood vessels and slows the rate of vision loss. This procedure takes about 20 minutes.
  • Laser surgery. Eye care professionals sometimes treat certain cases of wet ARMD with laser surgery, though this is less common than other treatments. This treatment is performed in a doctor’s office or eye clinic. It involves aiming an intense beam of light at the new blood vessels in your eyes to destroy them. However, laser treatment also may destroy some surrounding healthy tissue and cause more blurred vision.

Vitamins and Minerals

Some retina specialists believe that high doses of antioxidant vitamins and minerals may reduce the risk of progressing macular degeneration. However, this has yet to be proven. In spite of the uncertainty, there are companies advertising and marketing vitamins for macular degeneration. The nutrients under investigation include vitamin A, vitamin C, vitamin E, beta carotene, lutein, selenium and zinc. A few studies have shown that people with lower blood levels of particular antioxidant nutrients have a greater likelihood of having macular degeneration. However, no study has yet shown that taking nutritional supplements offers any significant reduction in the risk of developing macular degeneration – or in the progression of macular degeneration.

Recently several health food remedies have also become very popular among patients with macular degeneration. These include bilberry and St. John’s wort. There have been no formal studies of these supplements and no data to indicate any beneficial effect. But there are risks associated with the use of nutritional supplements.

One factor to consider is cost. Since many patients may take these supplements for years, the expense can add up to a significant amount of money.

Patients with macular degeneration often have other medical problems and may be taking several medications. Adding another daily pill may increase the risk of patients getting confused or discouraged about the number of medications they are on. This could result in failing to take other essential medicines.

Finally, very high doses of certain vitamins may have toxic effects. Megadoses of zinc have been associated with anemia. Megadoses of vitamin E have been linked to increased risk of lung cancer in smokers. Some of the supplements increase bleeding.

Research

Unfortunately, current treatments for macular degeneration are limited. While we can often limit vision loss, after treatment we usually are left with some damage to the vision. We usually cannot recover vision damaged prior to the treatment. Furthermore, there are many patients who are not candidates for the standard laser treatment. Because our treatment options are limited, extensive research is underway in this area. Clinical research trials at Illinois Retina Associates related to macular degeneration are summarized here:

Age Related Eye Diseases Study (AREDS)

The Age-Related Eye Disease Study (AREDS), sponsored by the federal government’s National Eye Institute, has found that taking high levels of antioxidants and zinc can reduce the risk of developing advanced age-related macular degeneration by about 25 percent.

This major clinical trial closely followed about 3,600 participants with varying stages of ARMD. The results showed that the AREDS formulation, while not a cure for ARMD, may play a key role in helping people at high risk for developing advanced ARMD keep their remaining vision.

Complication of ARMD Prevention Trial (CAPT)

This multi-site trial, coordinated by the University of Pennsylvania, used low-intensity laser to treat drusen in people with dry ARMD. The study has been completed but participants are still being followed.

The hope was that applying laser to the drusen might be able to get rid of them and improve or preserve vision. In fact, the treatment did eliminate some of the drusen, but the vision gain was not large.

However, one arm of the study was terminated when a disturbing side effect occurred. Patients with wet ARMD in one eye and dry ARMD in the other were part of the study. When the laser was applied to the dry ARMD eye, it seemed to trigger wet AMD in that eye. This did not occur to patients who had dry ARMD in both eyes.

Comparison of Age-related macular degeneration Treatment Trials

Results of the National Eye Institute’s Comparison of Age-related macular degeneration Treatment Trials (CATT) indicate that bevacizumab (Avastin®) is equivalent to ranibizumab (Lucentis®) in the treatment of wet ARMD when using similar dosing regimens, according to results published in 2012. The study also showed that monthly dosing produced slightly more vision gain than an as-needed regimen. The final visual results, however, were similar in all treatment groups, regardless of dosing frequency, with 60 percent or more of the patients achieving driving vision (20/40 vision or better).

Lucentis was specifically designed to treat ARMD, receiving U.S. Food and Drug Administration approval in 2006. Avastin, which is FDA-approved as a cancer treatment, is frequently used as a treatment for ARMD as it works in a similar manner to Lucentis due to the two drugs’ structural similarities. The CATT study was designed to compare the relative safety and effectiveness of the two drugs in treating wet AMD. The multicenter study enrolled 1,185 patients at 59 research and medical institutions across the United States.

Beyond the clinical findings of the study, the cost differences between treatments may have implications for both patients and physicians. One dose of Lucentis costs approximately $2,000, while Avastin costs about $50 per dose. Both drugs are manufactured by Genentech.

 

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