Macular degeneration is most commonly a natural result of the aging process. With time, the retinal tissues break down and become thin. This deterioration causes a loss of function of the macula.
In about 10% of cases of macular degeneration, aging of the retina is compounded by leakage of the tiny blood vessels which nourish the retina.
Growth of new, abnormal blood vessels in the scar tissue that forms from the leaking blood vessels is also common. Blood and leaking fluid destroy the macula, causing vision to become distorted and blurred. The formation of dense scar tissue blocks out central vision to a severe degree.
Occasionally, macular degeneration is caused by injury, infection, or inflammation. The disease may also be hereditary.