Sometimes, inner sight takes over when you're looking at something else.
This ring didn't start with the centerpiece, it started with wanting to make a ring that had the stones set on the shoulder as you see here. Simple, two-bead settings inside engraved star-style cuts. It occured to me that I could build a setting that had a similar shape, so I cut the center third out of a sterling dome, soldered it back together and channel-set the single stone to emulate the shoulder cuts... which is when I realized it looked like an eye. Of course, I then saw that the shoulder settings themselves also looked like eyes, which is when I realized I'd created the Third Eye Ring.
As to why the third eye is so much larger, well, it's clear to me that if I didn't realize what I was making while I was making it, I wasn't seeing with my physical eyes to begin with, but being guided by a different kind of vision.