Fans do not know what exactly happened to Zoro's eye. Zoro has never talked about this mystery, nor has Mihawk ever hinted at it in all the appearances that he has made in post timeskip One Piece ...

Since the time skip, Roronoa Zoro's closed left eye has sparked intense speculation among One Piece fans. Theories range from a concealed demonic power to a key for unlocking a final, powerful form.