Macular degeneration

Alternative names:

age-related macular degeneration (ARMD); senile macular degeneration (SMD)

Definition:

A progressive disorder that affects the central part of the retina causing gradual loss of central vision.

Causes, incidence, and risk factors:

The macula is the part of the retina that distinguishes fine details at the center of the field of vision. Degeneration results from a partial breakdown of the insulating layer between the retina and the choroid (the layer of blood vessels behind the retina). Destruction of the retinal nerve occurs when fluid leaks into the choroid and forms scar tissue. Macular degeneration is common in the elderly and is considered a process of aging. The incidence increases with each decade over age 50 to almost 35% by the age of 75. Other risk factors are family history, cigarette smoking, and being Caucasian. This disorder results in the loss of central vision only, and peripheral fields are always maintained.