Never mind. I just looked it up. Apparently, it's an app that you use with your smartphone or iPad. It lets you hold up your smartphone or Ipad in front of average, ordinary signs that morph into one of those messages that appear on the walls in DmC. Basically, you're seeing the world through DmC Dante's eyes. Hence the name, "The Eye of Dante."
What happens if you take a picture of the DmC game or a box of cookies? Or yourself? o_O --- Newer isn't always better. And I shall keep Dante's Force Edge polished and sharp till he comes back.