Mangekyo Sharingan user's who somehow didn't go blind

[Sage of Doujutsu]

Now we all know that Uchiha's who awakened the MS eventually start losing their eye-sight, right?(rhetorical don't actually answer this part) For example, Itachi went almost completely blind, Madara and Sasuke both used the eye's of their brothers to regain their vision. So my main question why didn't Izuna, Shisui, Kakashi or Obito start to lose their vision? I mean I can understand Izuna and Shisui because they were hardly ever shown or mentioned to have used it, but Kakshi and especially Obito have been spamming the hell out of their Kamui, kinda like Itachi using Tsukyomi and Amateratsu and like i said earlier he practically went blind... so why did those three inexplicably get a pass on losing their eyesight?

 

[The Necromancer]

Well Kakashi did go blind, and Obito had Senju DNA.

 

[Your Creepy Stalker]

Kakashi did start to go blind near the end of the war arc, and before that he hadn't spammed it so much.

As for Obito... Senju DNA? Not really explained why he doesn't go blind, and Senju DNA is just the fan answer.

 

[lord seventh]

I don't know about obito but kakashi start getting blind

 

[NarutoX28]

Kakashi did and he mentioned it.

Obito didn't as he's an Uchiha and so he could tolerate it better than Kakashi could (who only went nearly blind towards the End of the War Arc) and possesses Senju DNA.

Izuna likely did when we consider the fact that Madara realized that his eyes were losing "its light" and Shisui likely didn't as he used it sparingly which makes sense when Koto takes 10 years to recharge.

 

[V h o]

Well Kakashi did go blind, and Obito had Senju DNA.

Your answer

 

[lndra]

Why do you think that many Uchiha sought out their brothers and sisters eyes to obtain an eternal light? There's a reason why Itachi mentioned there were so many failed attempts at trying to fix their blindness.

The reason for Obito lasting longer is probably due to the Senju DNA that became apart of his body. Whether it completely healed him, or prolonged the process is unclear. However it doesn't matter because he could use it without trouble.

 

[Yang release]

Obitos MS is where his hashi cells are thats why he doesnt go blind

 

[SenseiSama]

Obito was powered by Senju and White Zetsu cells, his eyes were continuously rejuvenated in a similar fashion to Tsunade rejuvenating her body to stay young. Shisui didn't go blind immediately because his jutsu isn't convenient to use frequently unlike Amaterasu or Tsukuyomi and because he died before he could use his MS a good umber of times.