How the Human Eye Functions
The eye functions on much the same principle as a camera. The cornea has the effect of a glass lens and represents the foremost lens of the camera. When the cornea sees the image of an object, it does the focusing work. This image is then sent to the pupil that represents the aperture of the camera. This image is focused further by the lens inside the eye that represents the remaining lenses which are incorporated into camera lens. This focused image at this time is upside down. Finally, this reverse image is transmitted to the brain for processing by the retina, which resembles the film inside a camera.