I got classes in my pre-teenage years, can't remember exactly but maybe around the age of 11 or so. I was wondering how my class mates could easily read far away text, which to me appeared all blurry. Now, as I have grown older I can still read without classes, but the range of clear vision has become rather short - anything further than 40 cm starts to get blurry. I have noticed that this sometimes leads to rather non-ergonomic work practices, like bending closer to the screen, with tilted head so that I can look past the glasses. Luckily, this only happens when doing some very detailed work, like picking vertices one by one in Blender.