Word on how eye tracking support will work in Assassin's Creed Rogue can be found in Tobii's announcement of the game's support of the Tobii EyeX Dev Kit and SteelSeries Sentry, which "showcases the next evolution of human interfaces in gaming." They describe how this creates an "infinite screen effect" as the scene on the monitor will scroll with the players eyes. On the "chicken and the egg" problem that so many alternate controllers face (enough customers need to buy the $200 device to inspire developer support, while more game support may be required to inspire purchases of the controller), Ars Technica notes the Tobii Arcade page lists other games with current or future support for the technology. Here's a trailer showing this in action, and more on the process:

With traditional keyboard and mouse inputs intact, players using the Sentry with Assassin’s Creed® Rogue will experience true gaming immersion when their gaze and that of Shay Patrick Cormac, the game’s protagonist, are one and the same. For example, as the player looks to the left of screen, Shay Patrick Cormac will look to the left of his environment and the scene camera will pan to accommodate the exploration of this new visual territory creating an “Infinite Screen” experience. No longer will PC players be restricted to the size of their screen to orient Shay Patrick Cormac’s field of view and further explore the environment; the game auto-pans intuitively and in harmony with the player. Players can revert to their traditional mouse control by simply grabbing it. Assassin’s Creed® Rogue will also pause and resume automatically if the player looks away from the screen and back again, preventing disruptions in gameplay.

“Assassin’s Creed® Rogue with eye tracking aligns the gamer’s and a character’s senses so naturally, creating a truly immersive gaming experience. We’ve added an intuitive and natural modality without inhibiting the player’s ability, taking anything away or having to make a trade-off that lessens Assassin’s Creed® Rogue’s enjoyment for the gamer,” said Werner.