The focusing of an image with the human eye is similar to the way a camera focuses a picture. Light rays enter the eye and are bent through both the cornea and lens. The pupil acts like a camera shutter and will open and close to regulate the amount of light that enters the visual system. Most of the bent light rays that enter the eye must come together to a single point on the retina for us to see an image perfectly. If the cornea and lens cannot achieve this together, then glasses or contact lenses are needed. The retina acts like the film in a camera and receives the imprint of the picture, sending it on to the brain for final processing. These several different parts of the eye work together to create the image in front of you. If any of these parts of the eye are not functioning correctly the images you are viewing will be impacted.