Originally Posted by platinumrug

Well with the way that Kishi has drawn Kabuchimaru, he resembles Orochimaru more than he does his normal self. So to keep some of his old character intact and to not get the viewers confused, he kept the signature glasses. It could also be Kishi is trying to make Kabuto not entirely like Oro, and have him keep his sense of self, and his glasses are apart of his past and who he WAS, so keeping them makes him feel like himself and not a complete rip off of Oro. My explanation at least.