English▸ noun [mass noun] Medicine a degenerative condition affecting the central part of the retina (the macula) and resulting in distortion or loss of central vision.
There are two types of macular degeneration. Wet macular degeneration, which may progress rapidly, is characterized by the build-up of fluid under the retina, causing bleeding and scarring that leads to sight loss. Dry macular degeneration tends to progress more slowly and is characterized by the gradual deterioration of the visual cells, without build-up of fluid.