What is Age-Related Macular Degeneration or AMD?

By Arturo E. Betancourt, MD

Baltimore Washington Eye Center

. http://www.bweyecenter.com/

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What is Age-Related Macular Degeneration or AMD?

Age-Related Macular Degeneration (AMD) is the most common cause of irreversible blindness in patients over 65. The underlying defect appears to be loss of the barrier function of a layer beneath the retina called the Retinal Pigmented Epithelium (RPE). The breakdown of this layer that normally acts as a barrier, allows for abnormal blood vessels to invade the retinal tissue and cause leaking and bleeding, thus decreasing vision.
Are There Different Types of Macular Degeneration or AMD?
“Dry” Macular Degeneration (AMD) presents clinically as Drusen Formation, which are seen as small deposits under the retina and/or atrophy of the Retinal Pigmented Epithelium (RPE) layer. The result is a loss of the barrier function to blood vessel growth. Dry Macular Degeneration is the most common type of AMD and accounts for 85-90% of cases. Also, most patients with dry AMD have relatively good functional vision. Only 10% have severe vision loss. Thus, this type of macular degeneration usually has a fairly good prognosis for overall vision.
“Wet” Macular Degeneration (AMD) is due to a breakdown of a weakened RPE layer through which abnormal blood vessels can grow and leak fluid and blood. This causes swelling of the retina and can cause scarring and significant vision loss. Wet AMD accounts for only 10% of all cases seen, but accounts for 90% of severe visual loss in AMD.
Is There Treatment For Macular Degeneration or AMD?
The treatment for dry AMD is to have you carefully observe your vision and make certain that it doesn't look bent, distorted, tilted or changed in any significant way. The best way to do this is to use an Amsler Grid frequently at home to test your vision. In addition, taking a specially formulated daily multivitamin may help preserve your vision if you have dry AMD.
If caught early the treatment for wet AMD involves eliminating the abnormal blood vessels that have formed under the retina. Thanks to advanced research in blood vessel formation, it is possible to use therapeutic injections of compounds called anti-VEGF factors to cause these blood vessels to close up. These drugs are called Avastin and Lucentis and require repeated injection into the eye to be effective. Even so, to be effective requires early diagnosis through regular eye examinations because if bleeding and scarring have occurred it is usually too late to use therapeutic injections inside the eye.
The best overall treatment for AMD is prevention and early diagnosis through regular eye examinations.