Age-Related Macular Degeneration

See also: Macular Degeneration
What is it?
Age-related macular degeneration is a condition in which the cells of the macula, the center part of the retina, progressively degenerate, causing blurred central vision.
Who gets it?
Age-related macular degeneration affects middle-aged individuals and occurs more often in females than males. The risk for developing macular degeneration increases with age, and may be higher in people who smoke, have high cholesterol, light-colored eyes, or a family history of the disease.
What causes it?
The retina is a light-sensitive membrane that lines the inner part of the eye and is connected to the brain by the optic nerve. The macula is the central part of the retina. It contains cells that are responsible for sharp central vision. What causes damage to these cells is not known for sure, but it could be caused by hardening of the arteries that supply blood to the retina. Most people develop a form called dry age-related macular degeneration where the cells of the macula gradually disappear, so the macula becomes thin. As little as 10 percent develop wet age-related macular degeneration. With this form, blood vessels grow in the layer of tissue under the macula. As they grow toward the macula, they may leak blood and other fluids under the macula, damaging it.
What are the symptoms?
The main symptom of age-related macular degeneration is blurred central vision, which looks like a blind spot right in the middle of your vision. You might first notice it when reading, driving, or watching TV. Macular degeneration does not affect peripheral (side) vision or the ability to see colors. Dry age-related macular degeneration usually begins in one eye, but may affect the other eye at a later time, or it can occur in both eyes at the same time. The dry type progresses slowly until central vision is very poor. Wet age-related macular degeneration causes the same symptoms, but they occur more rapidly. Lines that should be straight may also look wavy or distorted.
How is it diagnosed?
Age-related macular degeneration is diagnosed through an eye exam. Your doctor will test your vision by having you read an eye chart. He or she will also show you a card with a grid pattern and a dot in the center. This is called an Amsler grid and is used to test central vision. You will stare at the dot and tell the doctor if there is any distortion in any area of the grid. He or she may also dilate your pupils for a better view of the retina. Yellow deposits, called drusen, on the retina can be a sign of the disease. Your doctor may want to perform a procedure called fluorescein angiography. A healthcare professional will inject a dye into a vein, then photograph the retina. These photos will help your doctor determine if there are any leaky blood vessels behind the retina.
What is the treatment?
There is currently no treatment for dry age-related macular degeneration, which progresses so slowly. You can improve your vision with special lenses called low vision aids. Wet age-related macular degeneration can be treated with laser surgery. The laser is used to destroy the abnormal blood vessels behind the retina and stop further loss of vision. Right after the surgery, vision will be blurry and you may feel some discomfort in the eye. Your doctor will continue to monitor your condition with fluorescein angiography during routine visits. It is not unusual for more new blood vessels to grow after existing ones have been destroyed. Your doctor may recommend another type of laser surgery, called photodynamic therapy. With this procedure, you receive an injection of a photosensitive dye that affects the abnormal blood vessels. They become sensitive to a special laser light, which then destroys only the blood vessels and no other tissues of the retina. Research into anti-angiogenic drugs may hold promise for treating wet macular degeneration. This treatment would disable the molecules that stimulate the growth of blood vessels.
Self-care tips
Everyone should see an eye care professional for a regular eye exam. If you are at risk for age-related macular degeneration, your doctor may give you an Amsler grid to check your central vision periodically at home. Contact your doctor any time you notice a change in vision. People with dry age-related macular degeneration may benefit from a diet low in saturated fats and high in antioxidants, found in vitamins C and E and beta-carotene, as well as zinc and copper. Talk to your doctor before changing your diet or taking supplements. Not smoking can reduce your risk of age-related macular degeneration and of recurrence of the wet type after laser surgery.