<P> Cone cells , or cones , are one of three types of photoreceptor cells in the retina of mammalian eyes ( e.g. the human 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 . The commonly cited figure of six million cone cells in the human eye was found by Osterberg in 1935 . Oyster 's textbook ( 1999 ) cites work by Curcio et al. ( 1990 ) indicating an average close to 4.5 million cone cells and 90 million rod cells in the human retina . </P>
where are the cones in the eye located
in the fovea centralis