Central Maine Eye Care
Treating Medical & Surgical Diseases of the Eye
John D. Lonsdale, M.D.
Troy M. Avery, O.D.
Melissa S. Frank, O.D.
Macular Degeneration
Macular degeneration (age-related macular degeneration or AMD) is a disease of the macula - a small area in the retina at the back of the eye. The macula allows you to see fine details clearly and do things such as read and drive. When the macula is not functioning properly, central vision can be blurry and have areas that are dark or distorted. Macular degeneration is the most common cause of severe vision loss in people over 50.
Although macular degeneration reduces central vision, peripheral vision often remains intact. For example, you may be able to see the outline of a clock but not be able to tell what time it is.
What causes Macular Degeneration?
Aging is the most common cause of macular degeneration. Over time, light processed by the macula can result in oxidative stress on the tissue. Many people (approximately 1 in 3 Caucasians) have genetic changes that make them more at risk more macular degeneration.
Major risk factors for Macular Degeneration are:
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Being more than 50 years old
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Having a family history of macular degeneration
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Cigarette smoking
Another risk factor may be elevated cholesterol levels. Many people with AMD have deposits under the retinal called drusen. Drusen alone does not usually cause vision loss, but when they grow in size or number, there is an increased risk of developing advanced AMD.
"Dry" or Non- Exudative Macular Degeneration
Ninety percent of people with AMD have the "dry" form. The oxidative stress on the macula results in thinning of macular tissue. Vision loss is usually gradual. Individuals with this form of AMD often have difficulty in adjusting to changes in light. For example, they may find it takes them some time to adjust to seeing indoors when they come in from outside.
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"Wet" or Exudative Macular Degeneration
Roughly ten percent of people with AMD have the "wet" form. Many of these individuals suffer significant vision loss. Wet AMD is a result of the formation of abnormal blood vessels underneath the retina. These new vessels leak fluid or blood and blur central vision. Vision loss may be rapid and severe. Fortunately, advances in therapy for wet AMD in recent years has allowed sufferers to maintain better vision and to dramatically slow the progression of the condition.
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