Musnad Ahmad 907:11

Abu Qatan narrated to us, Shu'bah narrated to us, from Simak, from Jabir ibn Samurah, who said: "The Messenger of Allah, peace and blessings of Allah be upon him, was *ashkal al-'ayn* (having streaks of red in the whites of his eyes), and *manhus al-'aqib* (having little flesh on his heels)."