Board Thread:Theories and Speculation/@comment-24120130-20150429143032/@comment-3965545-20150429204147

"He barely held his own against the Kage

Sasuke got unwilling help from Karin

getting Itachis eyes is a similar power up to 9-tails chakra"

He would have died against only Danzo if not for Karin..

Karin was always willing to help him..

and the only thing EMS does is take away the strain, make eyesight permanent, and boost the Dojutsu and ninjutsu of the users eyes according to DB4 Sasuke's profile.