Macular Degeneration Is caused when part of the retina deteriorates. The retina is the interior layer of the eye consisting of the receptors and nerves that collect and transmit light signals from the eye into the optic nerve, then to the brain for interpretation as our sense of vision. The macula is the central portion of the retina and is responsible for detailed vision and color vision, the vision we use to read, thread a needle, sign a check, or recognize faces. The macula is a highly specialized part of the nervous system and the eye in which the photoreceptors that react to light stimulus and the neurons that interpret and transmit these signals are precisely organized and densely compacted. It is the macula that allows humans to see 20/20, or an eagle to spot a small rodent on the ground hundreds of feet below.
Age-related macular degeneration is the leading cause of legal blindness in people older than 55 years
There are two types of age-related macular degeneration:
1. Dry (atrophic) form: This type results from the gradual breakdown of cells in the macula, resulting in a gradual blurring of central vision. Single or multiple, small, round, yellow-white spots called drusen are the key identifiers for the dry type. These spots are located in the back of the eye at the level of the outer retina.
2. Wet (exudative or neovascular) form: In the wet form of macular degeneration, newly created abnormal blood vessels grow under the center of the retina. These blood vessels leak, bleed, and scar the retina, distorting or destroying central vision. Vision distortion usually starts in one eye and may affect the other eye later. In contrast to the dry type, vision loss may be rapid in the wet type of macular degeneration.