Light rays pass through the cornea and then through the lens.
The lens forms an image on the retina in the back of the eye where the optic nerve is located. Sight is controlled by the optic nerve, the only nerve of vision. This nerve activates the retina to pick up the image in view. If the cornea is cloudy or scarred from an eye injury or disease, vision becomes blurred. Scar tissue and other disorders can block light rays and prevent normal vision.