Musnad Abu Ya'la al-Mawsili 42:375

Zuhayr narrated to us, Ubayd Allah ibn Musa narrated to us, Shayban narrated to us, from al-A'mash, from al-Minhal ibn 'Amr, from 'Abd al-Rahman ibn Abi Layla, from Abu Sa'id al-Khudri, who said: The Messenger of Allah (may Allah bless him and grant him peace) came out to us while in his hand were truffles. He said: "These are from the Manna, and their water is a cure for the eye."