My debatable factoid is that all vision is movement-dependent, including human vision, and so the bigness and wonderfulness of the tyrannosaur's eyes is beside the point of whether it needed its prey to move around in order to perceive it.

https://en.wikipedia.org/wiki/Stabilized_images , https://en.wikipedia.org/wiki/Fixation_(visual) , https://en.wikipedia.org/wiki/Microsaccade

We fake the movement of anything we're staring at, by means of tiny automatic eye movements, in order to remain able to see the thing at all.