Yeah when it comes to these eyeless masks I've always imagined that they either A) have lenses like all the others, but they're just designed to "blend in" with the mask itself so you can't tell from the outside which part is solid mask and which is actually see-through for them, or B) they have a tiny camera or sensor on the outside that relays everything they're looking at back to an internal screen, which appears much bigger and essentially just gives them a normal-sized view of their surroundings.