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A degenerative disease that causes the loss of vision in the central
part of the visual field. Also referred to as Age-Related Macular Degeneration (AMD
or ARMD), this disorder is the most common cause of vision loss among individuals
over age 65 and the leading cause of vision loss in America. The exact cause of
the disease is unknown.
The macula
is located in the center of the
retina. It is responsible for providing sight in the center of the
visual field and allows for reading and viewing objects in fine detail. When the
macula becomes damaged, central vision is impaired, but peripheral vision is unaffected.
People who have macular degeneration experience diminished vision, but do not become
blind.
There are two main types of macular degeneration: dry and wet. The dry
form is the most common and is due to the thinning of macular tissue with age. It
tends to develop slowly and results in gradual loss of vision. Wet macular degeneration
occurs with much less frequency, but presents a much more significant threat of
sudden vision loss. This form occurs when neovascularization (growth of new blood
vessels) takes place beneath the retina. These new vessels tend to be weak and often
leak blood an other fluids. This leakage may cause a significant blind spot in the
center of the visual field.
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