Cornea and sclera The cornea and sclera form a spherical shell which makes up the outer wall of the eyeball.
11. Cornea and sclera The sclera is :- principally collagenous,- avascular (apart from some vessels on its surface)- relatively acellular. It is perforated posteriorly by the optic nerve, and by sensory and motor nerves and blood vessels to the eyeball. The cornea and sclera merge at the corneal edge (the limbus).