It's true, Sans is short--even having gained a foot now that he's a human, he stands at five feet tall. In the name of continuing not to be an asshole, he paces himself with the steps of the blind guy, considering his words at the same time. Not used to this could mean a few things, and one option--that this guy really did just wake up suddenly blind--is alarming enough that he's going to have to ask.

"So, obviously the location's new. Is it the cane or the whole deal?" Sans needs to know if you can just lose senses that even humans have here. By now he knows he's lost his magic, but that follows with having a human body. If this place might take away more than that... Well. That's why he's asking.