The sclera runs from the cornea at the front of the eye to the back, where the optic nerve is. It surrounds but does not cover the iris, which is the colored part of the eye. The word "sclera ...

It's so well constructed. You've got the iris, the cornea, the pupil, and the sclera, are all working together to allow us to see. The eye muscles have to be fast. Just to track an object involves ...