I can't remember precisely did I learn the third eye from this movie ( Inner Worlds, Outer Worlds, great movie btw) https://www.youtube.com/watch?v=08CnDSQelNg&list=PLD8E5F0D70B62BEFE

but I was getting to the idea that we are born with the ability to see the other realm, but we lose that ability and even awareness of ourselves as we grow up, because focusing too much on the outside.

And recently, I was exposed to an idea that our eyes are actually a filter to "protect" ourselves from seeing other things because some can be scary, it is kind of making sense now.