The human eye is a complex sense organ that takes in light from the world around us and sends visual information to the brain. Light passes through the cornea in front of the eye to the lens. The cornea and the lens help to refract (bend) the light rays and focus them on the retina at the back of the eye. The retinal cells absorb and convert the light to electrochemical impulses, which are then transferred to the brain through the optical nerve.