Macular degeneration is an eye disease that occurs when there are changes to the macula. The Macula is a small portion of the retina that is located on the inside back layer of the eye. It reduces central vision and makes seeing details for close work, like reading or sewing, difficult or impossible. Macular degeneration is the leading cause of vision loss among people over age 50.

There are two types of age-related macular degeneration.

In the "dry," or atrophic type, the tissue of the macular becomes thin and stops functioning properly. This is thought to occur as part of the aging process and vision loss is usually gradual. 

"Wet," or exudative macular degeneration is less common and results when fluids leak from newly formed blood vessels under the macula and blur central vision. Vision loss from the "wet" form can be rapid and severe.