Majormario said:
I presume most of us know that pupil-less eyes only exist in animes and video games, and my question is how does one's eyes get to become pupil-less? In fact, why do some characters have just white spaces for eyes? Is it genetics, supernatural mind-control, or a surge of power that gives one the pupil-less eye?
In religious, psychological, and artistic history, the eye has always been considered to be the window to the soul. We consider it to be innately human. So, when the state of the eye is visually altered, it causes us to insinctually question the person's humanity: whether it be their sentience or presence of mind. Not having a pupil makes us feel like the person, literally, does not have a mind--or at least they are not fully present in their mind.
The anime characters who don't have pupils are typically evil, prone to trances, or are possessed. Characters who usually have pupils, but lose them temporarily are usually possessed, unconscious, mentally preoccupied, or dead. The pupils are a simple and universal visual metaphor for a person's state of mind.
Other times, though, it's just a stylistic choice. Look at Soul Eater--pretty much all of the characters in that series don't have pupils, except on special occasions. They aren't really going for soul allegories; that's just how they decided to draw the characters.