What is macular degeneration ?

Degeneration of the macula in the retina of the eye, which can lead to blindness. A nutritious diet helps prevent macular degeneration, as does protecting the eyes from ultraviolet light.

I think you meant muscular degeneration...and that is when your muscules deteriate.

Macular degeneration, often called AMD or ARMD (age-related macular degeneration), is the leading cause of vision loss and blindness in Americans aged 65 and older. Because older people represent an increasingly larger percentage of the general population, vision loss associated with AMD is a growing problem.

AMD occurs with degeneration of the macula, which is the part of the retina responsible for the sharp, central vision needed to read or drive. Because the macula primarily is affected in AMD, central vision loss may occur.

Archives of Ophthalmology in 2004 estimated that 1.75 million U.S. residents now have significant symptoms associated with age-related macular degeneration, with that number expected to grow to almost 3 million by 2020.

Deterioration of the macular cells in the eye... basically it leads to blindness, but u may get to keep your peripheral vision.

Macular degeneration is a medical condition in which the light sensing cells in the macula malfunction and, over time, cease to work.
Although some macular dystrophies that affect younger individuals are sometimes referred to as macular degeneration, the term generally refers to age-related macular degeneration (AMD).

A chronic disease of the eyes caused by the deterioration of the central portion of the retina, known as the macula, which is responsible for focusing central vision in the eye.
in people over sixty it is the most common cause of blindness, in which the macula becomes covered with scar tissue.

Macular degeneration is a common eye disease that causes deterioration of the macula, the central area of the retina where light-sensitive cells send visual signals to the brain. Sharp, clear vision is processed by the macula. Damage to the macula results in the development of blind spots and blurred or distorted vision.
When the macula becomes damaged, many daily activities such as driving and reading become increasingly difficult. Macular degeneration usually affects individuals older than 50 years of age, and scientific evidence shows that genes may play a role in the development of nearly three out of four cases of this devastating eye disease.
As on today there is no treatment which reverses macular degeneration.