Something odd I noticed while active focusing

So for fun, I thought I’d stare into a mirror and watch my eyes when I did active focus. Since I’m still about thee diopters myopic, I can get rather close to the mirror, making depth perception quite effective.

What I did was place myself at the right distance for focus, then move back a few centimeters, then active focused to clear up the view. What was wild was what I saw. My eyes receded into the eye sockets a bit!

I did it several times to make sure, but my eyes actually back up in the socket a little bit as the view clears while I’m doing active focus. I’d say the movement is something like a millimeter or two.

Has anyone else noticed this behavior when actively focusing into a mirror?

I did with camera, not mirror, but should be the same. I could see a absolutely no difference when I did AF.

It could have been an optical illusion or something. The best way to tell is to have a macro-style lens on a video camera or something (so small changes can be observed), position it to the side of the head, then record it. I might do that sometime if I have time to cross-check what I saw in the mirror.

It’s also possible the eye movement (if it exists) is unrelated, just how I seem to trigger the actual AF mechanism.

I am mostly curious if anyone else had seen this (illusion or real)