There may be some correlation but there must be other factors. Doesn't fit my history. I'm myopic, -6.0 diopter, needed glasses starting in 2nd grade. Spent a lot of time outdoors as a kid (no computers, 3 channels of TV which was targeted at grownups except for Saturday morning). Being inside was boring.

Nearsightedness also runs in the family on my fathers side, but strangely none of my kids need glasses and they all grew up with much more TV and other screen time than I had.