Cone cells, or
cones, are one of two types of
photoreceptor cells in the
retina of the
eye. They are responsible for
color vision and function best in relatively bright
light, as opposed to
rod cells, which work better in dim light. Cone cells are densely packed in the
fovea centralis, a 0.3 mm diameter rod-free area with very thin, densely packed cones which quickly reduce in number towards the periphery of the retina. There are about six to seven million cones in a human eye and are most concentrated towards the
macula.