Raptor eyes are so big that they cannot move them. The bird has to turn its entire head to look around (that's where the idea that owls can spin their heads around comes from... they can't really, but they can turn their heads a LOT farther than we can!)
The eyes of a raptor are so important for their survival, that they have three eyelids. The third one is partially see-through (partly "transparent") which allows the birds of prey to protect their eyes when attacking prey and still have some sight.
Birds of prey have eyesight that is at least two or three times better than ours. Some can see a grasshopper from the other side of a football field! Golden eagles can spot a rabbit from over a mile away and owls have great night vision so they can hunt in the dark.