(Also known as the wedjet or udjat eye). In Egyptian art, a representation of the eye of the falcon god Horus. The eye of Horus had an apotropaic function, and so was often depicted on amulets placed inside mummy wrappings to protect the deceased in the afterlife. Web resource here.

Eye of Horus amulet. From Egypt. Faience and aragonite. Ca. 1070–664 BCE. Metropolitan Museum of Art, New York.