It's fluctuated from -4.5 to -2.5 over the years. Currently on the better end I think, but I haven't been to an exam in a long while. I have friends with lower than -5 and from trying on their glasses, I would also wear them if my vision was that bad. Even at -4.5 the only major annoyances were street signs and confusing people from far away though.
That's insane to me, I'm at around -3.5 and I feel highly handicapped when I don't wear glasses. I most definitely wouldn't drive without them for instance.
