Maybe it's like nearsighted- farsighted
In Predator, he is nearsighted, sees all red, needs the mask to blue it.
P2, he sees allways blue-ish, 20-20.
AVP- farsighted. Always red because that is what their eyes are used to.
But I think they see infra-red. Didn't Keyes say so, too?
'Course, what does he know.