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Keeping You in Sight
Keeping You in Sight
Age Related Macular Degeneration (AMD)
Age Related Macular Degeneration is a disease that affects your central vision. It is a common cause of vision loss among people over the age of 60. Because only the center of your vision is usually affected, people rarely go blind from the disease. However, age related macular degeneration can sometimes make it difficult to read, drive, or perform the other daily activities of life that require fine central vision.
The macula is the center of the retina which is the light sensitive layer of tissue at the back of the eye. As you read, light is focused onto your macula. In the macula, millions of cells change the light into nerve signals that tell the brain what you are seeing. This is called your central vision. With good central vision, you are able to read, drive, and perform other daily activities that require fine, sharp, straight ahead vision.
Age Related Macular Degeneration occurs in two forms:
Dry Age Related Macular Degeneration affects about 90% of those with the disease. Slowly, the light sensitive cells in the macula break down. With less of the macula working, you may start to lose central vision in the affected eye over time. It usually occurs in just one eye at first, but you may get the disease later in the other eye. Doctors have no way of knowing if or when both eyes will be affected.
Wet Related Macular Degeneration only affects about 10% of those with the disease. However, it accounts for 90% of all the severe vision loss from the disease. It occurs when new blood vessels behind the retina start to grow toward the macula. Because these new blood vessels tend to be very fragile, they will often leak blood and fluid under the macula. This causes rapid damage to the macula that can lead to the loss of central vision in a short period of time.
Neither type of Age Related Macular Degeneration causes any pain.
The most common symptom of dry AMD is slightly blurred vision. You may need more light for reading and other tasks. Also, you may find it difficult to recognize faces until you are very close to them. As dry AMD gets worse, you may see a blurred spot in the center of your vision. This spot occurs because a group of cells in the macula have stopped working properly. Over time, the blurred spot may get bigger and darker, taking more of your central vision. Often people with dry AMD do not notice any changes in their vision. With one eye seeing clearly, they can still drive, read and see fine detail. Some people may notice changes in their vision only when AMD affects both of their eyes.
An early symptom of wet AMD is that straight lines appear wavy. This happens because the newly formed blood vessels leak fluid under the macula. The fluid raises the macula from its normal place at the back of the eye and distorts your vision. Another sign that you may have wet AMD is the rapid loss of your central vision. You may also notice a blind spot. If you notice any of these changes in your vision, you should contact your ophthalmologist at once for an eye exam.
Dry AMD cannot be treated currently, but this does not mean that you will lose your sight. Fortunately, dry AMD develops very slowly. You may lose some of your central vision over the years. However, most people are able to lead normal, productive lives, especially if dry AMD only affects one eye.
Some cases of wet AMD can be treated with laser surgery. The treatment involves aiming a high energy beam of light directly onto the leaking blood vessels. Laser treatment is more effective if the leaky blood vessels have developed away from the fovea which is the central part of the macula. However, even if the blood vessels are growing right behind the fovea, the treatment can be of some value in stopping further vision loss.
Another treatment for wet AMD is Visudyne TM therapy. In this procedure, a light-activated drug called VisudyneTM is injected into the patient’s blood stream. Once the drug reaches the retina, it is activated by a non-thermal laser (a laser that does not burn the retina). This produces a clot that closes the abnormal vessels without causing damage to the overlying sensory retina. The abnormal vessel may return after several months. However, the VisudyneTM therapy can be reapplied at up to 3 month intervals if necessary.