Montion sickness is a very complex subject. The common view that it it is a disruption between what the eyes and ears balance system are telling our brains has some validity, but it is a gross oversimplification.
The simplification fails to explain, for example, why people get much less seasick while actually in (rather than on) the water
Other factors like proprio reception
play an important role.
As others have noted "blind" people often have enough vision to detect motion normally as this is more a function of peripheral rather than central vision.
Anyone who gets seasick should look up some the latest research
, as there are some practical lessons, for sailors.