MACULA LUTEA

in anatomy, small yellow area on the retina of the eye. When the gaze is fixed on any object, the centre of the macula, the centre of the lens, and the object are in a straight line. In the centre of the macula is a depression, called the fovea. The nerve cells sensitive to light rays are especially numerous in the macula. In the centre of the fovea the nerve cells are exclusively of the type known as cones, which are associated with colour vision and perception of fine detail, and there are no blood vessels to interfere with vision. Consequently, in this area vision in bright light and colour perception are keenest. Degeneration of the macula sometimes occurs in old age as a result of hardening of the blood vessels of the choroid. The disorder reduces central vision but does not interfere with peripheral vision (see also visual-field defect).