What is Macular Degeneration?
Age-related macular degeneration (AMD) is a degenerative aging process affecting the central retina of more than 10 million persons in the US. AMD occurs most frequently in persons over age 70 but can be seen as early as age 55. By age 70 we all run a 10% risk of having AMD. AMD also has a genetic component and if you have a strong family history of AMD your risk increases to 20%. Other risk factors for developing AMD are smoking, caucasian ethnicity, blue eyes, obesity, gender (females > men) and sun exposure. AMD is the most common cause of severe vision loss in the elderly.
Depending on the type of macular degeneration, there may be few options for treating the disease. But the good news is: numerous studies and research are being conducted that will, hopefully, offer more solutions in the future.
Located in the center of the retina, the sensitive macula provides us with sight in the center of our field of vision. When we look directly at something, the macula allows us to see the fine details. This sharp, straight-ahead vision is necessary for driving, reading, recognizing faces, and doing close work, such as sewing.
The two common types of macular degeneration are dry and wet. Dry macular degeneration accounts for 80% of cases and is caused by aging and thinning of the tissues of the macula. It develops slowly and usually causes mild vision loss. People often notice a dimming of vision when they read.
Wet macular degeneration is a much greater threat to vision loss even though it accounts for only 20% of cases. With the wet form of the disease, new blood vessels grow beneath the retina where they leak fluid and blood and can create a large blind spot in the center of your visual field. If this happens, there will be a marked disturbance of vision.
- Blurry or fuzzy vision
- Straight lines, such as sentences on a page, telephone poles, and sides of buildings, appear wavy
- A dark or empty area appears in the center of vision
How is Macular Degeneration Treated?
Although your ophthalmologist will be able to readily detect the disease during an eye exam, he or she won't be able to cure it. The goal is to help the patient see better and stabilize the condition.
There is no proven treatment to stop or reverse dry macular degeneration. However, a large scale study by the National Institue of Health, the Age Related Eye Disease Study (AREDS) has definitively proven that taking a very specific combination of vitamins and nutritional supplements will slow the progression of the disease and reduce the risk of future vision loss. The latest formula called AREDS 2 vitamins are available over the counter without a prescription. AREDS 2 contains vitamin C, E, zinc, copper, lutein and zeaxanthin. The role of these vitamins in preventing the start of macular degeneration has not been established.
Medical treatment for wet macular degeneration is now available under most circumstances. These medications (anti-Vascular Endothelial Growth Factor drugs) are given by an injection into the eye with a very small needle These drugs are proven to drasticly reduce the risk of severe vision loss. In 40 to 50% of patients an actual improvement in vision can be seen. The drug works by reducing or eliminating the abnormal blood vessels that are leaking in the retina. The anti-VEGF drugs are not a cure. Most patients with wet AMD will require 6 to 8 injections per year indefinitely, although newer drugs are allowing for longer intervals between injections.
Even though a minority of patients may progress to severe vision loss (not seeing the big E on the eye chart) they will never go blind from AMD. Because AMD only effects the macula or central retina and spares the peripheral retina, the patient will always maintain their side or peripheral vision. Patients who have lost some central vision may benefit from the use of low vision aids such as special glasses, magnifier, large print materials, telescopic devices, "e-readers", and closed circuit television magnifiers.
What is the Amsler Grid?
The Amsler Grid is a chart that can reveal signs of wet macular degeneration. You can get one from your ophthalmologist or print this one and test your vision at home. The chart is a tool for monitoring your central visual field. It makes it possible for you to tell if there are disturbances in your vision caused by changes in the retina. We suggest monitoring your vision once a week with the amsler grid if you have a history of AMD.
Here's how it works:
- Sit in an area with good lighting and hold the chart at eye level at a comfortable distance.
- If you wear glasses, keep them on, but cover one eye completely. (look through the bifocal segment of your lens)
- Stare with your other eye at the central dot on the grid. At the same time, observe the pattern of vertical and horizontal lines on the chart.
- Repeat the test with the other eye.
If you experience any of these changes, make an appointment with your ophthalmologist immediately:
- Distortion or curvy lines
- Holes or spots in some areas of the grid