Yep, just back and forth, make sure your eyes fully focus before switching. What I do is roughly 2 sec near, 2 sec far, etc, whole thing takes me maybe 30 seconds, but some people say to do it much more or wait as long as 10 sec before switching. Make sure to do it outside in the sunlight. Oh, and if you notice one eye focuses better than the other, then try it with just the bad eye.
There's all sorts of discussion online and it's a pretty heated topic, flamewars, paid courses, forums, some people say it can only prevent it, some say it can reverse it, some say it does nothing, some will ban you for talking about it, etc. Then there is the even more controversial theory that you can recover from serious myopia with the "reduced lens" method. The popular opinion is that that's impossible, but there are a good handful of datapoints to the contrary. Personally, my myopia was never that bad, so I never got too deep into that stuff and just did the basic near-far-near exercises outside in the sun and that was enough to reverse the small decline in my vision.
It makes a little sense, but I'm not sure it's good for your eyes.
My eye doctor had me come in first thing in the morning, then again the next day at the end of the day, after my workday, and my vision had degraded about -0.25 to -0.5 over the course of the day, which is apparently pretty typical. If your prescription is just a little bit off, your eye muscles will work a little harder to hold things in focus, but over the course of the day, they get strained and tired, and at the end of the day they can't do it anymore.
I can imagine if you really strength-trained those muscles, you could hold things in focus for longer, more comfortably, and inversely, I could imagine if you never really worked those muscles they'd atrophy somewhat.
But I'm not sure really straining those muscles all-day-every-day is healthy long term. It would be like sitting on a wooden stool all day during your workday and saying "all you need to do is keep your core muscles strong by doing x/y/z workout a couple times a day," versus just getting a decent ergonomic chair.
Nothing wrong with a workout or keeping your muscles strong, but in order to last a full lifetime, your muscles need lots of rest too, and I imagine getting proper glasses definitely helps.
I appreciate the perspective, but near-far-near focusing in sunlight isn't some unusual type of workout. It is how my genus kept their eyes in shape for the last few million years and there is pretty comprehensive evidence that a lack thereof is the main cause of myopia's increasing prevalence. In light of that, I'll stick to what I'm doing.
> degraded about -0.25 to -0.5 over the course of the day
FWIW my ophthalmologist made the point that most people working on computers have eyes go too dry toward the end of the day, and that also causes blurry vision. Try some eye drops.
> But I'm not sure really straining those muscles all-day-every-day is healthy long term.
Consider it "normal use of the muscle" and not straining and how normally using your muscles is considered good for you.
Personally, I expect a good chunk of the effect to be on the brain side, not in the physical muscle. Like how parents sometimes tell kids with a lazy eye to "use both your eyes". Keep the brain from giving up on it.
There's all sorts of discussion online and it's a pretty heated topic, flamewars, paid courses, forums, some people say it can only prevent it, some say it can reverse it, some say it does nothing, some will ban you for talking about it, etc. Then there is the even more controversial theory that you can recover from serious myopia with the "reduced lens" method. The popular opinion is that that's impossible, but there are a good handful of datapoints to the contrary. Personally, my myopia was never that bad, so I never got too deep into that stuff and just did the basic near-far-near exercises outside in the sun and that was enough to reverse the small decline in my vision.