Although there is no cure, are there treatments available for age-related macular degeneration?
- Dry age-related macular degeneration
Once dry age-related macular degeneration reaches the advanced stage, there is no form of treatment at present to prevent further vision loss. However, there is an intervention measure that could delay and possibly prevent intermediate age-related macular degeneration 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 nutritional supplements with a specific high-dose formulation of antioxidants (vitamins C and E and beta-carotene), zinc, and copper delayed or prevented the progression of age-related macular degeneration from the intermediate to the advanced stage.
A follow-up trial, called AREDS2, was completed in May 2013. In that study, researchers found that the addition of omega-3 fatty acids to the supplements did not improve the formula’s success. The antioxidants lutein and zeaxanthin proved safer than beta-carotene, which increases the risk of lung cancer for smokers or ex-smokers. Thus, the AREDS2 recommendation for the supplement formula is 500 milligrams of vitamin C, 400 international units of vitamin E, 10 milligrams of lutein, 2 milligrams of zeaxanthin, 80 milligrams of zinc, and 2 milligrams of copper.
- Wet age-related macular degeneration
Wet AMD can be treated with injections of angiogenesis inhibitors into the eye, with photodynamic therapy, or with laser surgery. None of these treatments will cure wet AMD, but each may slow the rate of vision decline or stop further vision loss. However, the disease and loss of vision may also progress despite treatment. Options should be discussed with a doctor.
Angiogenesis Inhibitors: Angiogenesis inhibitors work by blocking the activity of vascular endothelial growth factor (VEGF), a protein that promotes blood vessel growth.
Three treatments for wet AMD using angiogenesis inhibitors—EYLEA®, Lucentis®, and Macugen®—were approved by the U.S. Food and Drug Administration (FDA) in 2011, 2006, and 2004, respectively. There is also a fourth drug, called Avastin®, approved by the FDA as a blood vessel growth inhibitor to treat colorectal and other cancers, that has been used off-label (i.e., for purposes other than the approved uses) by some doctors to treat AMD.
EYLEA®: After numbing the eye, the doctor injects EYLEA into the clear, jellylike substance (the vitreous) that fills the eye from the lens back to the retina and then monitors the patient's progress. After an initial three-month period of injections every four weeks, EYLEA can be administered every eight weeks.
In comparison, treatments with the other angiogenesis inhibitors are normally given every four weeks (Lucentis and Avastin) or every six weeks (Macugen). The actual number of injections needed is determined by the physician, taking the individual patient's disease status and response to treatment into consideration.
The most commonly reported side effects of EYLEA (affecting no more than fi ve percent of patients) include hemorrhage of the conjunctiva (the membrane that covers the white of the eye), eye pain, risk of cataract, vitreous detachment, vitreous floaters (specks or clouds moving in the field of vision), and increased eye pressure. There is a greater risk for endophthalmitis (severe inflammation of the eye interior) and retinal detachments, as can follow any injection into the vitreous.
Lucentis®: Lucentis is also injected into the vitreous portion of the eye after it has been numbed. Injections are given regularly over a period of time. The frequency and actual number of injections needed are determined by the physician and the individual patient's disease status and response to treatment. Findings from international studies announced in 2012 indicate that an injection every four weeks may be optimal.
The most commonly reported side effects of Lucentis include hemorrhage of the conjunctiva, floaters, eye pain, increased eye pressure, and inflammation of the eye. Rare but serious adverse events include endophthalmitis, retinal detachment, retinal tear, increased eye pressure, and traumatic cataract.
Macugen®: Macugen is also injected into the vitreous portion of the eye that has been numbed. It is usually administered every six weeks. The actual number of injections needed is determined by the physician, taking the individual patient's disease status and response to treatment into consideration. Macugen is still available for treatment of wet AMD, but is not used as often as other injectable angiogenesis inhibitors.
Common side effects of Macugen include inflammation of the eye, blurred vision, other changes in vision, cataracts, bleeding in the eye, swelling of the eye, eye discharge, irritation or discomfort of the eye, and "spots" in vision. Injection can also make the eye susceptible to infection for a period of time.
Avastin®: Avastin is an FDA-approved cancer therapy drug manufactured by the same company that makes Lucentis. Avastin has been used by doctors as an off-label treatment for AMD. Both drugs are similarly administered. However, Avastin is much less expensive, and many doctors believe these drugs are equally effective against macular degeneration. The National Eye Institute of the National Institutes of Health conducted clinical trials (Comparison of Treatments Trials, or CATT) to study the relative efficacy and safety of Avastin and Lucentis. In May 2011, they 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 injected monthly. The report showed that receiving doses of either drug "as needed" was less effective for maintaining visual acuity than monthly dosing. Although Avastin was associated 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.
Photodynamic Therapy: Photodynamic therapy (PDT) is most effective in a subtype of wet AMD called predominantly classic subfoveal choroidal neovascularization, in which blood vessel growth and leakage in the fovea—the small region in the center of the macula—are well defined. It should be noted that PDT is rarely used now that there are drugs (EYLEA, Lucentis, Macugen, and Avastin) that specifically block the vessel-promoting VEGF protein. During the PDT procedure, a drug called Visudyne® is injected into the arm. The drug courses through the body and is absorbed by the fragile, leaking blood vessels in the eye.
Drug Safety Issues
Avastin®, a drug approved for cancer treatment, must be divided into smaller doses for use as an eye treatment. This is done by licensed "compounding pharmacies." Although use of a compounding pharmacy is an accepted practice, currently the compounded medicines are not individually evaluated by the U.S. Food and Drug Administration.
The compounding procedure can also introduce the opportunity for bacterial contamination of a drug product. Although rare, there have been illnesses and even deaths due to poorly compounded drugs. Consult with your doctor about how your Avastin and other off-label drugs are prepared.
For the latest news on this and other drug safety issues, visit the news updates section of our website.
Because Visudyne is activated by light, the doctor directs a low-intensity laser at the retina for a little over a minute. This activates the Visudyne, allowing it to destroy the abnormal vessels. One treatment normally takes about twenty minutes and is relatively painless.
The most common side effects of PDT include headache, injection site reaction, and blurred or reduced vision. Because the drug is activated by light, it is important to avoid exposing eyes or any part of the skin to sunlight or bright indoor light for up to five days after treatment.
PDT may help to stabilize vision, but it will not restore lost vision.
Laser Surgery: Laser photocoagulation surgery was the first treatment used for wet AMD, but it is only an option for a small number of patients. During the outpatient procedure, the eye is numbed, and a high-energy laser heats, seals, and destroys abnormal leaky blood vessels. This can potentially prevent further vision loss, but it results in a permanent blind spot due to scarring.
Some patients experience mild pain during and/or shortly after the procedure. When successful, laser surgery is done once. However, if new blood vessels grow, surgery may have to be repeated.
Implantable Miniature Telescope: Approved by the FDA in 2010, the implantable miniature telescope (IMT) may help those with end-stage wet AMD gain back some vision.
The tiny telescope is inserted into one eye, which then provides central vision while the other eye provides peripheral vision. The telescope projects images over healthy areas of the retina. The IMT can usually be implanted by an eye surgeon during an outpatient surgical visit. After surgery, patients must participate in a structured vision rehabilitation program to learn how to perform daily activities using the device.
Posted 30 Aug 2013
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