Eyes

Eyes are the organ that help us to see, and are one of the parts of the body's visual system. In humans, and indeed most other creatures on this planet, we have a lens in our eye that focuses light onto the retina at the back of the eyeball, which sends information about colour, brightness and shape. This can take either the form of a single lens, or a compound lens, like in insects. Simple organisms have eyes that can detect only the presence of light and dark.