What is the macula?
The macula is located in the center of the retina, the light -sensitive tissue at the back of the eye. The fovea is the center part of the macula and is the most sensitive part. The macula is responsible for central vision and reading vision. The macula has the most concentration of photoreceptor cells or light-sensitive cells. When the eye is directed at an object, the part of the image that is focused on the fovea is most accurately seen.
What is age-related macular degeneration (AMD)?
Age-related macular degeneration (AMD) is a leading cause of irreversible blindness among people 50 years of age and older. It is a deterioration of the macula that results in impaired central vision. People with AMD may have difficulty with daily tasks that require fine vision such as reading, driving, recognizing faces and dialing the telephone. There is no pain associated with AMD.
AMD occurs in two forms: Dry AMD and Wet AMD.
Dry AMD or dry macular degeneration (atrophic AMD) is the most common form of macular degeneration. This disease occurs when the light-sensitive cells in the macula break down, blurring the central vision in the affected eye. This form of AMD typically progresses very slowly and can less commonly lead to severe central vision loss. The most common symptom of dry AMD is a dark or blurred spot in the center of your vision. Dry AMD generally affects both eyes, but vision can be lost in one eye while the other eye seems unaffected. One of the most common early signs of dry AMD is drusen. Drusen are yellow deposits under the retina. These changes may cause distorted or blurry vision. Your family eye doctor can detect drusen during a comprehensive dilated eye exam.
Wet AMD may cause sudden loss of central vision. This occurs when abnormal blood vessels behind the retina start to grow under the macula. These new blood vessels tend to be very weak and often leak blood and fluid. The blood and fluid raises the macula from its normal place and the patient may experience distortion and straight lines may appear wavy. “Wet” AMD normally arises from pre-existing “dry” AMD. If you notice these symptoms or other changes to your vision, contact your family eye doctor at once.
What causes AMD and who is at risk?
The risk of developing AMD increases with natural aging. Other causes related to AMD include smoking, obesity, family history, high blood pressure or cholesterol levels and race (Caucasians are typically more likely to lose vision from AMD than African Americans).
To help preserve your vision, consider the following suggestions:
- Do not smoke.
- Focus on healthy eating with a diet rich in dark green leafy vegetables, such as spinach, mustard greens, collard greens and kale. Include dark fruits and juices, such as purple grapes, blueberries, plums and cantaloupe to help preserve your vision, as well as fish once or twice a week.
- Consider sun protection, such as sunglasses that block UVA and UVB light. Sunglasses that block blue light may also help protect against AMD. Maintain normal blood pressure and cholesterol levels.
- Take a vitamin/mineral supplement. Several are specifically designed for AMD. Ask your family eye doctor to learn more about these supplements.
How is AMD treated?
There are three possible treatment options for wet AMD: laser surgery, photodynamic therapy and injections into the eye. No treatment is a cure for wet AMD. However, treatments may slow the rate of vision loss or stop further vision loss. Unfortunately, vision loss can progress despite treatment.
Laser Surgery – This treatment uses a high energy beam of light that is aimed directly onto the new blood vessels and destroys them preventing further loss of vision. However, laser treatment may destroy the surrounding healthy tissue and some vision. Laser surgery is more effective if the leaking blood vessels have developed away from the fovea, the central part of the retina. The risk of new blood vessels developing after laser treatment is high and thus repeated treatments may be necessary. In some cases, vision loss may progress despite repeated treatment.
Photodynamic Therapy – PDT is a special type of laser treatment. In this treatment, a light-sensitive dye is injected into a vein. The dye is then taken up by the new, weak blood vessels in the retina. The laser targets the dye-filled blood vessels and destroys them. This treatment may cause less damage to surrounding healthy tissue than standard laser treatment. PDT may be suggested if you have wet AMD that affects the fovea. PDT may need to be repeated several times to be effective. Again, this treatment may stop or slow vision loss but does not restore vision.
Injections – Wet AMD can now be treated with new drugs that are injected into the eye (anti-VEGF therapy). Abnormally high levels of a specific growth factor occur in eyes with wet AMD and promote the growth of abnormal new blood vessels. This drug treatment blocks the effects of the growth factor. Multiple injections may be given as necessary. This drug treatment can help slow down vision loss from AMD and, in some cases, improve sight.