Board Thread:Theories and Speculation/@comment-890307-20161205161301/@comment-30426414-20161218154327

Ravenlot 27 wrote: Nope, that's not how it works. You seem to misunderstand the events. The original MS eyes are actually removed and replaced by the MS eyes of another person, which means that the removed eyes can be preserved somewhere. And the combined pattern of the EMS is the result of the interaction between the user's chakra and the newly-transplanted MS eyes of the previous user. There is no "merging" of the two sets of eyes or something, the original eyes are literally taken out to implant a new pair of eyes from your relative afterwards.

After doing some research, I found that's there's nothing confirming that the eyes are combined or swapped. However, it's implied that they're combined. Remember when madara took kakashi's mangekyo? When he transplanted it into his empty eye socket, the pattern of the sharingan didn't merge with madara's pattern, it stayed the same. Which means that it didnt become an EMS. Also if the eyes are just swapped, I don't see how that will cure the blindness or improve the users mangekyo techniques, it just makes more sense that they're combined.