Rods and cones photoreceptors in a human retina.
This is a confocal microscope image of rod and cone photoreceptors in a human retina. Fluorescent probes have been used to identify rod photoreceptors (green) and cone photoreceptors and horizontal cells (red). The cones looks like candle sticks, warped as if viewed through a fun house mirror. The horizontal cells are the round cells in the lower portion of the image.
Image courtesy of Dr. Robert Fariss, National Eye Institute, NIH