My wife and I are very nearsighted, but I cannot explain why our kids do not need glasses.
Does make one wonder. As a kid I spent way more time outdoors than indoors. Yet I am very nearsighted. My 3 three kids (now adults) have 20/20 vision and they didn't spend nearly as much time outdoors as I did when I was a kid.
Today’s kids don’t read as much as you did, when you were a kid.
Nearsightedness can occur if you do a lot of reading as a really young kid. If you do a lot of tasks and things that require a lot of intense close focus.