When I was a kid, I assumed that only rich kids wore glasses because they were expensive. I didn't think about it too much, because my eyesight was fine. While expense probably had something to do with it at that place and time, the global instance of myopia, or nearsightedness, has been growing at a rate that can't be explained by genetics. That's the bad news.
The good news is that researchers are pretty sure they know why more people suffer from myopia now. Most of the damage is done in childhood, but there are new and innovative treatments to keep it from getting worse, or even to reverse the damage in adults. And there are ways we can help our children's eyesight stabilize. More time spent outside enjoying sunlight and looking at faraway sights is the key. That's a great excuse to get out in nature with the family for a hike, as if you need one.