Board Thread:Naruto Discussions/@comment-24824148-20160724215526/@comment-27089028-20160729082734

Well, if he had replaced his right eye with another Uchiha's sharingan he would lose Kamui. The Eternal Mangekyo requires two things in the transplanted eyes:

-Close genetics i.e. Izuna and Madara, Sasuke and Itachi

- the other Uchiha whose eyes you will transplant into your sockets must have Mangekyo Sharingan as well.