Textbooks frequently misrepresent the optics of the eye. They often show rays bending at the eyelens, but not at the cornea. In fact, most of the bending is at the cornea. The eye lens acts only as a corrective element. After all, body tissues are mostly water, including the transparent tissues and fluids of the eye, so their refractive index is nearly the same as that of water. Most of the refraction occurs at the air-cornea interface, not at the lens because the change in index of refraction at the lens surfaces is only about 1/10 as great there as it is at the front surface of the cornea. The eye lens functions as a "correction" element, the strongest lens action is at the cornea.