The glasses have a blue liquid that can flow in front and around the eyes. The liquid stays horizontal with the ground, regardless of how the vehicle moves, and so provides stability to the eyes and the brain.
The glasses are similar in functionality to looking at the horizon when experiencing motion sickness on a boat. The stability of the horizon provides a reference point for our brains to lock-in on, alleviating the confusion that different senses create when they’re sending seemingly incompatible information.