[Bluestein]

It is a very sort of portable optimum. Why carry two lenses when one will do?

[fuzzfactor]

>my brain merges the two images so I still get depth but also everything is in focus.

This might beat bifocals.

[itishappy]

This is exactly how they do some bifocals, particularly contact lenses. It's also very relevant to surgical procedures like Lasik.

https://www.aao.org/eye-health/treatments/what-is-monovision...

[Steve44]

That looks exactly like what's happening, even down to "In fact, with both eyes open, they may not be able to tell which eye is set for distance and which is set for near."

Quick edit to add I didn't expect that to happen as was pleasantly surprised when I noticed it. For me it happens immediately and automatically, it just works.

[itishappy]

Suppose that's excellent news if you're ever interested in surgical correction!