Cornea
    
    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.