Before the printed paper, people wouldn’t know that they had vision problems, because they couldn’t/wouldn’t  read, thus it was impossible for them to diagnose such issue.

When the first books and newspapers came out, the population instantly knew there was something wrong with their sight.
Not every one, but some did.

Up until then, it was normal.
For everyone suffering from vision problems it was normal to see like that, because they couldn’t knew what was the baseline.

Sometimes we face the same problem everyday. It’s not a matter of tech evolution, but it also depends on how we listen to our body.

For example: Do you think you’re breathing correctly or not? What if there’s something missing and you’re not breathing 100%?

It’s easy to diagnose a big problem, but the small ones? They are often unnoticed because we think it’s the baseline, the normal thing, the usual.

In fact, aside from analyzing ourselves every day with tools, we can’t really know what’s normal and what’s not regarding our health status unless an evident problem arise.