A bit of history on the origin of the Evil Eye talisman/symbol:

In Turkey, wherever you look, you'll meet plenty of eyes looking at you. Glass evil eye beads. It is common in the Turkish culture to give a gift of a blue nazar Boncugu (nazar boncuk) or the evil eye bead as it is more widely known. People hang a small evil eye amulet from the rear view mirror of their car, keep several small evil eye beads or evil eye charms on hand to give to guests, hang an evil eye near their door in the home or office. Glass evil eyes are worn, in the form of jewelry also. 

Throughout the whole human history, in every culture and religion, the eye figure has been considered as a powerful talisman to defy evil forces.  At almost every stage of human history, man has looked for the assistance of magic objects called talismans to defy evil forces. Evil eye charms have survived to this day.