They either just dealt with it or they became functionally "blind". Even today most "blind" people are not 100% blind but just have eyesight that can't be corrected into a functional state.
So, there are a few important aspects here. One is that modern lifestyles increase the prevalence of poor eyesight. Living indoors and looking at books or screens increases myopia. Not focusing on far away objects outside has an impact on eyesight, so historically people who spent so much time outside would have had lower incidences of myopia.
Additionally, there are degrees of poor eyesight. Typical poor eyesight is in the "things are a bit fuzzier than they should be" range, not "can't see at all without glasses" range. While that would be a quality of life issue, it may not be functionally super important for day to day life in pre-modern times. Reading especially puts a very high burden on eyesight. And driving adds an even greater burden, because it adds the requirement to be able to read signs from far away (due to the speeds involved). Those are unusual requirements, which historically wouldn't have been as relevant.
More so, eyesight tends to degrade over time as people get older, and the activities that would be most demanding of good eyesight might typically be done by younger individuals (say, 20s vs. 30s, 40s, or older). Such as fighting in war or hunting.
A lot of tasks in pre-literate societies wouldn't have a high requirement for good eyesight. And for those that did, folks who didn't have good eyesight would simply be barred from doing them. Keep in mind that prior to the industrial age the vast majority of the population would have been involved with food production, either farming or herding, neither of which have a particularly hard requirement on good vision.
Sadly though, there still would have been some folks who had eyesight that was so poor that it would have rendered them effectively blind though with modern glasses they might have been able to be functional members of society. Those folks would have had a very poor time, and possibly relegated to being taken care of by their communities. Or, in urban environments, becoming beggars. There's a reason why the "blind beggar" is such a well-worn trope in fiction and literature, because historically there wasn't much that could be done to help someone with very poor eyesight, and they'd have a hard time making a living.
Follow up question: would these people be seen as disabled/crippled/invalid/pathetic, or would this be seen as "natural" with age like eg arthritis?