I don't think he's actually looking at anything, rather he's listening. I think this came from "Seconds" where Clark is sitting with his parents, berating himself for letting Luthor get away with "Wanda."
Clark is hearing Luthor on an ultra-high frequency audio signal trying to get Superman to meet with him just before he blows up a building.
Clark, upon hearing Luthor's voice, says, "Luthor!"
