I worked on a foveated video streaming system for 3D video back in 2008, and we used eye tracking and extrapolated a pretty simple motion vector for eyes and ignored saccades entirely. It worked well, you really don't notice the lower detail in the periphery and with a slightly over-sized high resolution focal area you can detect a change in gaze direction before the user's focus exits the high resolution area.
Anyway that was ages ago and we did it with like three people, some duct tape and a GPU, so I expect that it should work really well on modern equipment if they've put the effort into it.
Anyway that was ages ago and we did it with like three people, some duct tape and a GPU, so I expect that it should work really well on modern equipment if they've put the effort into it.