The transparent, slightly concave cornea fits into the less curved sclera
by means of a flattened groove. The cornea is a transparent, elastic body
which lacks blood vessels and tissue structures. It contains only a few cells.
The metabolism of the cornea is slow as it is only supplied with nutrients
from tear fluid, ocular chamber fluid and the vessel plexus at its rim. Together
the cornea and the sclera form a stable and resistant capsule, the 'skeleton'
of the eyeball, with a high tensile strength.