Because the experience of someone whose impaired vision is fully corrected gives little to no special insight into what it is like to be blind. (If you spend y

Because the experience of someone whose impaired vision is fully corrected gives little to no special insight into what it is like to be blind. (If you spend years where the best vision you get is worse than, 20/200 or whatever, because you don't actually have access to adequate correction, that is actually relevant to discussions of blindness even if your vision is in principle correctable, sure.) Blind people have to adapt their lives in ways that are just not reflected in taking off one's glasses for a moment or wearing a blindfold for a bit. And when you're as myopic as a -10, the times when you go without correction are typically momentary because not having correction is not optional for you. At the same time, the anxiety (terror, even) of suddenly trying to navigate the world sightlessly, whether because you're a visually impaired person whose glasses have been lost or crushed or because you're a signted person wearing a blindfold for a day as an exercise, isn't really representative of everyday blind life, either. 'Legally blind without my glasses' is a phrase that at best invites inapt comparisons, and in other cases falsely suggests the authority of highly relevant firsthand experience. It's not the biggest deal in the world. I wouldn't say it's offensive. But it's just not a very clueful thing to say when talking about blindness or talking to blind people.