I'm hella nearsighted since I was very young, and knowing genetics, I'll probably only get more blind, so I upgrade to the really fancy glasses (so I don't end up with huge ass bottle glasses--and I still end up with huge ass bottle cap lenses, honestly) but luckily at that fanciness, my glasses and contacts have a blue light filter as a part of them. Also, I use a low blue light monitor, which is apparently better for you than a cintique, which apparently has a lot of blue light, but I dunno if that's every model.
I try and step back from reading close up stuff if it's been an hour or so--otherwise you do get more nearsighted with time, something my eye-doctor was always telling me, when I was very young and a huge bookworm. It also helps to have plenty of light, and try not to squint. but...TBH if you're going blind...you're just gonna go. It's a part of growing older, and while there are exercises you can do, they do not beat genetics.
I have a friend who's been nearsighted for years, just so many years, and only when he had to take his drivers test (he was like 24 when he did, long story) they were like "yo...you are blind. Go to Walgreens. Get some glasses" and he was a little miffed because he had done the whole holistic eye exersizes all growing up, he took vitamins, he took breaks, he did all that good stuff. But genetics are genetics, and ever since he got that pair--his entire life has been so much better. It cured his headaches, improved his mood--like...if you do think you're going nearsighted...you might actually be going nearsighted, and it might not make any difference if you are or are not using a screen because...genetics.