Sclera

The sclera is the white, tough, fibrous outer layer of the eyeball containing collagen and elastic fibers. It envelops all of the eyeball except the cornea. It is also called sclerotic.

The sclera constitutes the posterior five sixths of the connective tissue coat of the ball of the eye, providing an attachment for the extraocular muscle insertions. The sclera is perforated by plenty of nerves and vessels which passes through the posterior scleral foramen.