Re: Our own vision uses it...
It works because we look around a lot. And we don't notice what we don't see.
Something that I don't remember doing before in an eye test: the optician asked me to look ahead while he moved his hand around - I was to say when I saw his fingers wiggling. I assume he was wiggling throughout the test, but for an evidently not unusual amount of time, I was aware of the hand but not the wiggling. I repeat, this is a test of SIGHT.
My test in 2016 was somewhere else and included a screen behind which lights twinkled and I was to click when I saw one, which I think I messed up by breathing on the screen and misting it up so that a lot of it couldn't be seen.
Biting the hand that feeds IT
