Master of the Soul Techniques
Sasuke has proven himself and now Itachi will offer up his eyes to Sasuke so that Sasuke can fulfill his destiny of being even stronger than Madara, becoming the strongest ninja in the world and thus its rightful ruler. At least that's the only thing I can think of other than he laughs at Sasuke and gloats on how he still didn't win, even after trying so hard. "I did myself in, brother. Ha ha ha!"