Illustration of a section through the eye showing details of a healthy eye (top right), an eye with dry macula degeneration (right centre) and an eye with wet macula degeneration (bottom right). The macula is the area of the retina, the light sensitive membrane at the back of the eye, responsible for central vision, which is the sharpest. It is not known what causes macular degeneration, although old age, poor nutrition and overexposure to the ultraviolet radiation in sunlight have all been implicated. The main symptom is a loss of central vision.