When I was a teenager and first got glasses, my mum took me to someone who claimed that her methods could stop and even reverse eye damage. I was dubious about this, for many good reasons (my mum's tendency to believe in all sorts of alternative health charlatans, for one), but to my surprise this one actually seemed to offer some fairly practical exercises.
I don't know about the more excitable claims - I doubt it's that easy - but given that a lot of us are spending more time looking at screens and staying indoors this year, I offer you the ones that I remember.
IIRC, she recommended doing these every day - should take up about 15 mins in total. I am not organised enough to do that, but I figure occasionally is better than never.
Changing focus: stand at a window, or somewhere with sufficient distance, and hold up one finger in front of your face, at arm's length. Focus on the finger, and then on the window (it works better if you have something to focus on, like a sticker, not just the glass), and then at something outside. You can extend this in steps as far as your view goes. Keep going back and forth for a couple of minutes, finger / window / outside / window / finger, and back again.
Bouncing a ball: get a small bouncy ball, stand on a hard, flat surface, and bounce it. Follow its path with your eyes. Annoy your neighbours!
Relaxing your eyes: sit down with your elbows on something, e.g. a table or desk. Let your head rest with the heel of your hands in your eyesockets. Let your eyes relax, and try to stop controlling their movements, as much as possible (this is super hard to do!). Sit like this for 30 seconds to a minute. Be cautious with this one - listen to your body, and if it hurts, stop. Also to note, passing people are quite likely to ask if you're okay, because this position expresses Maximum Despair, so, like - pick a place where people aren't going to freak out.
Vitamin D: when it's sunny, stand with your eyes closed and your face up to the sun for five mins. I don't know how effective this one is, but it makes you feel like a little kitty or a lizard, basking in the sun. Not part of the exercise, but I recommend doing this one while listening to nice music, for a moment of zen in your day.
Note: I don't claim that these will fix your eyes, but they always felt like a good thing to be doing - like stretching exercises. Personally, I've done them very inconsistently through the years, so YMMV as to how effective they are.
Also please note that my short-sightedness is fairly minor, and stable, and I don't have any medical contraindications. I'm not a doctor, and you know your own eye health better than me, so if these seem like they would cause you strain, please don't do 'em.
