I used reading glasses for years.

Then I started drinking a pint of kombucha, most days. I got my accommodation back, no more reading glasses! Other improvements too, e.g. blood pressure, skin elasticity.

I can't think of anything else to attribute the improvement to. I would never have guessed anything would help. (No guarantees, but would welcome other reports, positive or negative.) This is one of those "anecdotal" things where you might as well, because there is only potential upside, plus tasty hydration, no down. Like getting your Tdap booster (free at the drug store), because why not?

A pint of kombucha runs US$2.50-$4 at the supermarket. But I brew mine for <$0.20.

Ok, that sounds kind of whacky but very intriguing. Can I ask what age you are and if you measured your current accommodation power (like: how many diopters can you accommodate now)?

Old enough to notice skin elasticity. My reading glasses were +1.5. I still use them for extra-fine print, so there are limits.

Is your brew carbonated? The stuff at the grocery store says it's naturally carbonated but I have no idea how it all works

Kombucha includes also yeast which metabolizes sugars and releases CO2 so it has some natural carbonation like e.g. beer does.

I have a times added 1/2 tsp of dextrose ("corn sugar") before I tighten down the bottle lid, to boost fizz. (Beer brewing trick.)