But as it is necessary for the perfection of sight that we be able to see objects nearby and at a distance, and as it is impossible for the rays leaving an object at different distances to converge exactly on the retina, as I have proved, a God placed the crystalline lens, whose refraction is greatest, between the other two humors, and suspended it by the ciliary ligaments in such a way that it can withdraw from the retina somewhat when objects are too near to be seen distinctly.