Board Thread:Theories and Speculation/@comment-25132842-20180405032134

Kakashi had a Sharingan transplanted into the eye that he lost. However, when he activated the Mangekyo after he killed Rin, he suffered damage to his eyesight just like any other Uchiha before getting the Eternal Mangekyo.

Is this because Obito had not already activated the Mangekyo before he transplanted it? Like, if Obito attained the Mangekyo and then transplanted it into Kakashi's eye, would Kakashi's Mangekyo, once activated, be "Eternal"? 