IIRC snappy eye movement makes us essentialy blind not only during the movement itself, but for a brief time after the eye settles also.
Foveated rendering (where IR cameras look where pupils are looking, passing this info to PC and the frames rendering with high detail only in that spot) was already demonstrated to be working well and fast enough to not be noticable.
It is not present in any consumer VR headset, and the software side is also not yet plug&play