Board Thread:Naruto Discussions/@comment-24898250-20140730025315/@comment-24531362-20140803062156

Actionmanrandell wrote:

all of what you said was assumptions aside from how the sharingan is created you can not in any way shape or form say that the chakra leaves the eye. i can disprove that based on the fact the energy of the eye must mold with his body so that he can actually use the eye they are connected

For the love of Kishimoto, man, really. The whole reason the Uchiha have the Sharingan and the other clans don't is because only they can produce the special chakra needed to create and properly utilize the dojutsu. The reason that Kakashi's reserves sucked after getting Obito's eye was because he did not have this chakra. His reserves never stopped sucking, so he never got this chakra. He could use the eye because Rin surgically connected his optic nerve to the eye. Thus, his optic nerve was never mutated by the special chakra he never had, so he could only use techniques inherent in the eye, while he had the eye itself.