There's an interesting correlation between a huge increase in myopia cases and the increasing popularity of smartphones. In all likelihood it goes back to the advent of the printing press. It's not a coincidence that "four eyed" kids are historically associated with stereotypes of being nerdy or studious. The ciliary muscle contracts when you see something close to your face, and it relaxes when you look at something at a distance. So staring at something close to your face all the time keeps the muscle contracted for too long, probably causing/worsening myopia. So go touch grass anon, do it for your eyes.