The Eye of Olan is a fetish created by the Prince Olan, so that he was able to foresee the future and protect his lands from the enemy.
Its is an orb shaped object, much like a crystal ball held within a green wire cage. He would hold it aloft and chant the words ' By the powers of the eye give me sight beyond sight', the orb would glow and then show what his enemies would do in their next battle. All of this so that he could protect his father's (King Eldar Cervum) kingdom.
However due to his curse (see Curse of Prince Olan) the Eye became corrupted.