Now, coming to the theory I’m going to share. As we know constantly using Mangekyou Sharingan ultimately results in blindness until and unless the user doesn’t have eternal Mangekyou Sharingan which has no such side effects. But in my opinion, Sarada Uchiha can use her Mangekyou Sharingan continuously without losing her eyesight.
Well, first of all, we know that Sarada Uchiha is at least attempting to learn medical ninjutsu. And in my opinion, she will become an expert in using medical ninjutsu and even surpass her mother Sakura Haruno and the Fifth Hokage of Konohagakure, Tsunade Senju. So, this will mean that Sarada would eventually inherit the Strength of 100 Seals jutsu from her mother.