Information on the causes and symptoms of macular degeneration.

Dry Macular Degeneration

Dry macular degeneration is the early stage of the disease. It may be caused by the aging and thinning of the macular tissues, the deposition of pigment in the macula, or by a combination of the two processes. Yellowish spots known as drusen begin to accumulate from these deposits or from the debris from deteriorating tissue, and this occurs primarily in the area of the macula. Loss of central vision may occur very gradually but can be as serious as the wet neovascular form of AMD.

Wet Neovascular Macular Degeneration

Approximately, 10% of dry AMD cases will progress to a more severe, advanced form of eye disease known as wet macular degeneration. Wet macular generation occurs when new blood vessels grow (neovascularization) beneath the retina and leak blood and fluid into the surrounding tissue.

The leakage of blood and fluid causes permanent damage to the light-sensitive retinal cells. These cells then die off and blind spots are created in the central vision. During the process of neovascularization, the body attempts to create a new network of blood vessels to supply more nutrients and oxygen to the eye's retina. This process fails and instead creates scarring that leads to a loss of central vision.

Wet forms of macular degeneration are further classified into two general sub-types – classic and occult. Classic choroidal neovascularization (CNV) is usually associated with severe vision loss. It occurs when blood vessel growth and scarring has very clear, delineated outlines observed beneath the retina. Occult neovascularization produces less severe vision loss and new blood vessel growth beneath the retina is not as distinctive and leakage is less obvious.

Diagnosing Macular Degeneration

The diagnosis of macular degeneration is based on an examination of the eye by an eye specialist or ophthalmologist. The initial tests include an examination of the retina as well as measurement of the sharpness of vision. A brief test using an Amsler grid that measures your central vision may be performed. A doctor may ask you about any symptoms of macular degeneration you are experiencing.