A rare 2,500-year-old marble discus was found last week by an Israeli lifeguard diving in the underwater antiquities site of Yavne-Yam, an ancient port city settled in the middle Bronze Age and inhabited until the Middle Ages. (Today, the beach is named for the nearby kibbutz of Palmahim.)
The convex object is believed to have been fixed to the front of ancient ships as a talisman, its shape and painted circles connoting the pupil of a forward-looking and vigilant eye to protect mariners from misfortune. Kobi Sharvit, director of the Marine Unit of the Israel Antiquities Authority, explained it is known from drawings on pottery vessels, coins and other historic sources from the 5th century BC that this model was very common on the bows of ships and was used to protect them from the evil eye, acting as a pair of eyes to aid navigation and warn of dangers. Variants of the decoration are still common on modern boats in Portugal, Greece and other coastal countries, and eye-shaped amulets and good luck charms are extremely common throughout the Mediterranean.
Posted about this earlier, but this link has a photo of the object.