Board Thread:Theories and Speculation/@comment-25132842-20180320052324/@comment-31099706-20180320053355

There is also a third method, by implanting Hashi cells in a big scale, like Obito. But that's kind of similar to how you get the Rinnegen, though.

I don't get what you're asking in your second sentence, but if it's about if further usage of MS while having Rinnegen can cause eye damage, then I don't know. But for all I know, you can't use the Rinnegn along with the Sharingan. That's only unique to Sasuke.

While Madara did change his eyes, it was during his edo period. And he stopped using it just after he became alive. So it's hard to tell if he can or not.