Good vision: It’s something that many people take for granted. For a growing number of older Americans, however, their good vision is being threatened by a disease called macular degeneration. This month, Suburban Hospital’s Chairman of Ophthalmology, Dr. S.M. Sastry, talks about macular degeneration and what you need to know to protect your vision.
To support those in our community who suffer from age-related macular degeneration, Suburban Hospital is launching a new support group in September. The group’s meetings—held one Saturday a month from 9:30 to 11 a.m.—are free and offer an opportunity to learn the latest in eye treatments and research from the area’s leading ophthalmologists. For more information about joining the group, call 301.896.2463.
What is macular degeneration?
Age-related macular degeneration (AMD) is the leading cause of new cases of blindness in patients over 60 years of age. It is a degenerative disease of the macula, which is the central part of the retina and affects the central vision.
Does macular degeneration cause total blindness?
No. Macular degeneration normally affects only your central vision, not your peripheral vision. This means that it usually doesn’t cause total blindness. Because the central vision is affected, however, you may eventually experience difficulty with activities such as reading, driving, and recognizing people’s faces. This can greatly affect your quality of life.
How many people are affected by macular degeneration?
Macular degeneration is an age-related eye disease that currently affects as many as 15 million Americans. As the population ages, there has been an escalation in the number of people suffering from the disease. That’s why it’s important to know about prevention, detection, and treatment so that the effects of the disease can be minimized.
Are there different forms of AMD?
Yes, there are two forms of macular degeneration: Dry AMD and Wet AMD. Nearly 90 percent of patients suffering from AMD have dry AMD. With dry AMD, yellow-white deposits called drusen accumulate in the deep macula of the eye. This leads to interference in the function of the photoreceptors responsible for processing light coming into the eye, which in turn causes a decrease in vision. In its most advanced stage, dry AMD can result in significant central vision loss.
While most cases of dry AMD remain in the dry form, approximately 10 percent of cases progress to the more severe form called wet AMD. With wet AMD, abnormal choroidal vessels leak fluid, or rupture and bleed, causing severe and often permanent central visual loss.
What are the risk factors for AMD?
The greatest risk factor for AMD is age. That’s why it is so important for anyone over the age of 65 to see an ophthalmologist for regular retinal exams. Other possible risk factors include smoking, UV exposure, hypertension, and family history. While some of these risk factors cannot be controlled, things like smoking, sun exposure, and hypertension can be.
What can I do to decrease my chances of getting AMD?
There is increasing evidence that what’s healthy for your heart is healthy for your eyes. This means that it’s important not to smoke, to keep your cholesterol levels within healthy ranges, and to control your blood pressure. Additionally, it’s important to protect your eyes from sun damage. The cumulative effects of sun exposure begin when we are young, so always wear sunglasses and a hat when outside. It’s also important to maintain a healthy diet that includes green leafy vegetables such as spinach, collard greens, kale, and broccoli.
What are the symptoms of dry and wet AMD?
Because AMD occurs without pain, the first symptoms that people usually notice involve changes in vision. With dry AMD, you may notice that you need more light to read, that your vision is slightly blurry, and that you don’t recognize faces. While dry AMD usually affects both eyes, you may notice these vision changes in only one eye.
With wet AMD, you may notice that straight lines appear wavy. The loss of central vision can occur quickly with wet AMD, making it all the more important to be aware of any changes in vision and to seek medical help quickly if any changes occur.
How is AMD diagnosed?
Because the first symptoms that are noticed with AMD are changes in vision, it’s best to see an ophthalmologist immediately if you suspect a change in your eyesight, especially a change in your central vision. Your ophthalmologist will utilize a number of tools as part of a comprehensive eye exam.
If you have already been diagnosed with dry AMD, you can evaluate your eyes on a daily basis, monitoring them for signs of wet AMD, by using something called an Amsler grid. You can request this grid from your eye doctor.
How is dry AMD treated?
There is no cure for dry AMD and the damage caused by either the dry or wet form of macular degeneration is not reversible. Therefore, the goal is to slow the rate of decline.
With dry AMD, the National Eye Institute’s Age-Related Eye Disease Study (AREDS) has found that for those who have reached the intermediate stage of the disease, a vitamin formulation of antioxidants and zinc reduces the rate of progression of the disease. This in turn may help many people reduce the rate of decline in vision.
It’s important to note that AREDS therapy has only been found to be helpful with intermediate or advanced AMD, and then only under specific conditions. For instance, people who smoke should avoid high doses of vitamin A since its use may increase the risk for lung cancer. Similarly, high doses of vitamin E can thin the blood, a risk to those already on anticoagulation medication. Therefore, it’s important to talk with your doctor about what stage of AMD you have, your risk for developing advanced AMD, your other health factors, and what medications you currently take.
How is wet AMD treated?
With wet AMD, it’s important to treat the wet lesions under the supervision of a retina specialist. Traditional treatments include the use of lasers and photodynamic therapy (PDT). Laser treatment is considered most often when the blood vessel leakage is outside the center of the macula. The laser is used to destroy the leaking blood vessels, preventing further loss of vision. The risk of laser treatment is that scar tissue can form, and repeated treatments may be necessary. For these and other reasons, only a small number of those who suffer from wet AMD are considered good candidates for this procedure.
With PDT, doctors use a combination of drugs and light therapy to slow the rate of vision loss. A drug called verteporfin is injected into the arm and then travels into the eye. A light shined into the eye activates the drug, destroying the new blood vessels. This slows the rate of vision loss. Results of PDT are often temporary, however.
The newest form of treatment for wet AMD involves the use of drugs that are injected directly into the eye. Called anti-VEGF therapy, these drugs have demonstrated good success in controlling the growth of abnormal blood vessels. Three anti-VEGF drugs are currently being used: Macugen, Lucentis, and Avastin.
The anti-VEGF procedure takes place in the physician’s office using a topical anesthesia. With any of the drugs used, multiple injections are required; therefore, good follow up is crucial to the success of anti-VEGF therapy.
Are there any new treatments or possible cures for AMD on the horizon?
The most promising research under way involves retina transplantation — the transplantation of healthy cells into a diseased retina. Researchers are also looking at certain anti-inflammatory drugs in the treatment of wet AMD.
About Dr. Sastry
Dr. S.M. Sastry is a board-certified, fellowship-trained ophthalmologist specializing in retina, macula, vitreous diseases, and surgery. He has been selected as one of “America’s Top Ophthalmologists” and serves as Chairman of Ophthalmology at Suburban Hospital. He has a special interest in the treatment of macular degeneration and diabetic retinopathy and performed several thousand retina procedures. Dr. Sastry received his medical degree in India in 1989 and a Master’s degree in Public Health from Harvard University in 1990. He completed a staff fellowship at the National Eye Institute (NIH) and a two-year vitreoretinal fellowship at the University of Washington.
Dr. Sastry’s office is located in the Camalier Building, 10215 Fernwood Road, in Bethesda. For more information, go to www.bethesdaretina.com. Dr. Sastry can be reached at 301.896.0101.