[geeB]

You can do that cheaply by picking up a pair of reading glasses, or glasses with lower power if you are already nearsighted. Roughly, infinity will be at 1/diopters in meters, so +0.5 glasses will make 2m away at infinity, +1.0 at 1m, and so on, and similarly if you are at -3, -2.5 will make 2m infinity, etc. It's not exact because they are not thin lenses and there is a separation between lens and eye, but it should be pretty close.

I've been using one less diopter correction for a while most of the time, with an additional pair of glasses with the full prescription for driving. Not sure if it does anything or my nearsightedness just naturally stopped progressing though, but since it's working and not bothering me I have no interest in finding out.