Board Thread:Theories and Speculation/@comment-1251315-20160617185646/@comment-25122992-20160617193055

What do you mean by "taking" and "pairing"? The rules of eyes' transplantation are pretty simple in the Naruto universe - you can just take out any eye from a person, just one or both, and transplant it into yours or someone's else eye socket with no problems (although some medical knowledge still would be useful for this). Another question is that you must be physically and mentally able to handle the eye's power if it's a doujutsu of any kind. Obito had a plenly of Sharingan eyes collected from the Uchiha corpses after the clan's massacre and he possessed enough skills to transplant any of them and be able to use it (he's also an Uchiha, after all).