Can't it just be in the requirement of the exam? If they have connected glasses, they have to remove them for the duration of the exam and use them only after leaving the room. If they are spotted with them, they get disqualified instantly?

Edit: IMHO the accessibility argument would not stand for a written exam as those glasses are often used to transcribe audio. If it's written there is nothing to transcribe thus is not required. Those glasses are also more expensive than the non connected one so economically speaking if they can afford these glasses, they sure can afford the non connected ones. If they don't have a pair of non connected glasses they have to plan ahead of the exam which typically happens weeks if not months after the beginning of the semester so it's on them to plan accordingly.

TL;DR: forbid them in school ToS.