Therans are known to be telepathic, and it's related to eyesight.

You can telepathically speak with anyone at a distance, and just know it's "someone" if they are hidden.

If you can see people, you can telepathically know they are somewhere in Thera. If they are in the same area, you can know exactly where they are.

If you can't see people, you can still telepathically sense that they are awake, but you have no idea who or where they are.

It seems more IC that you can vaguely sense that someone exists more than some other stuff. Why is it that you can't sense someone outside the east gate if you are one step away at the eastern crossroads, but you can sense someone at the western crossroads all the way across town? (I don't really care, just an example.)

Anything that happens, you can think of a way to make it IC, if you want to. You can also think of away to make it OOC, if you want to.