This infamous symbol is associated with Horus, the sky god who is represented either as a falcon or as a falcon-headed man. Son of Isis and Osiris, he set out to avenge his father who had been murdered by his uncle. While fighting against him for the throne of Egypt, Horus’s left eye was injured but restored by his mother’s magic to full health. The eye of Horus thus came to symbolize the process of healing or making whole. As an amulet, the wedjat eye ensured the protection and wholeness of the wearer.
For more, see Yasmin El Shazly's article ‘Dung Beetles & Sandal Straps’ from Rawi magazine’s Issue 7 available online (link in details).