The best answer is Sclera. The sclera is the tough outer coat of the eye that covers the eyeball except for the cornea. It is a tough opaque tissue that serves as the protective outermost coat of the eye and provides structure and strength to the eye. It is also known as the white of the eye. Attached to the sclera, are six small muscles that control the movement of the eye. In elderly people, the sclera may appear yellow in color.