Seliece
D: Mangas tend to do that alot. Back when I was still reading Inuyasha because I was naive and thought that was the best thing since sliced bread, they never told us why Kaede had an eyepatch either.
Aaaand, like Bleach, they never told us a whole bunch of things there yet crying
I think they might soon, since he's sort of using his "eye powers" as I call them XD
lol! My friend and I have a joke about how all the plotholes in Bleach (an anime we're both quite fond of) are actually like blackholes, and the only thing holding the Bleach universe together is Ichigo's rippedness. It's not even physically possible to be as ripped as Ichigo, lol.
I do hope they tell us about Rabi's eye. I knew he had a perfect memory, but the "eye powers" as you so quaintly put it are new to me (and everyone else, for that matter). Any theories?