One could easily find a correlation between my need for glasses and the time at which I (and a lot of others) began using computers heavily, like being on a computer for more than 8 hours a day.
I, on the other hand, started using a computer heavily about 5 years after getting my first pair of glasses. Some of it is just genetic and not all myopia is preventable with just more time outside.
More time with computers is less time spent outside. Also, it might be a certain age when people start using computers (like when they have learned to read).
