Most fans of the series know that the usage of this dojutsu leads to blindness, although the easiest solution for this situation is Sarada getting the original eyes of her father, Sasuke Uchiha.

Hence, Boruto having his eye covered could be a sign that the flashback takes place only days or weeks after they fled the village. As seen in the sneak peek, Sasuke Uchiha was recollecting what ...