It's already implemented in the StarVR headset (which has 210° FOV) using Tobii eye tracking tech. They had a working demo at Siggraph a couple weeks ago.
> It’s crazy unbelievable how low-latency Tobii’s eye tracking is
Tobii uses cameras at 60 or 120 Hz, so >8 ms. It's the mature but old and limited tech. MEMS-based tracking is faster. During a saccade, you've the samples to predict where the eye is going to end up fixated, 20 ms before it happens.[1]
