Like many age-related disorders, macular degeneration was once rare, but has become increasingly common in developed nations in the last 30 years due to the rapid growth in the number of people over 75 and poses a significant health care challenge as it is the most common cause of vision loss in adults, with the bulk of new cases occurring after the age of 80. By 2020, it is estimated that as many as 3 million Americans will be affected.
Macular degeneration, often age-related macular degeneration (AMD or ARMD), is a medical condition that usually affects older adults and results in a loss of vision in the center of the visual field (the macula) because of damage to the retina. It occurs in "dry" and "wet" forms. It is a major cause of blindness and visual impairment in older adults, afflicting 30-50 million people globally. Macular degeneration can make it difficult or impossible to read or recognize faces, although enough peripheral vision remains to allow other activities of daily life.
The "dry" form of macular degeneration is characterized by the presence of yellow deposits, called drusen, in the macula. A few small drusen may not cause changes in vision; however, as they grow in size and increase in number, they may lead to a dimming or distortion of vision that people find most noticeable when they read. In more advanced stages of dry macular degeneration, there is also a thinning of the light-sensitive layer of cells in the macula leading to atrophy, or tissue death. In the atrophic form of dry macular degeneration, patients may have blind spots in the center of their vision. In the advanced stages, patients lose central vision.
The "wet" form of macular degeneration is characterized by the growth of abnormal blood vessels from the choroid underneath the macula. This is called choroidal neovascularization. These blood vessels leak blood and fluid into the retina, causing distortion of vision that makes straight lines look wavy, as well as blind spots and loss of central vision. These abnormal blood vessels and their bleeding eventually form a scar, leading to permanent loss of central vision.
Treatment can't reverse dry macular degeneration. But this doesn't mean you'll eventually lose all of your sight. Dry macular degeneration usually progresses slowly, and many people with the condition can live relatively normal, productive lives, especially if only one eye is affected. We may recommend regular eye exams to see if your condition is progressing. The wet form often requires treatment which may involve intraocular injections and or surgery.
Sources: The Mayo Clinic, WebMD