The OA : Seeking explanation for Nina and Khatun (spoilers)

I realize this was the plot device that pretty much sets the entire story in motion, but what on earth was so terrible in the world to justify Khatun "protecting" Nina by taking her sight from her so she wouldn't see the bad things in the world, or something along those lines? I know years later Khatun told the now-seeing Prairie that she could see all along, which sounded like a riddle to me. But what good did she think would come from plunging that little child into a life of darkness for so many years? It seemed to me more like a horrible punishment because Nina chose to go back to life with her father than a way to protect her.

I don't know if I remember it right, but it seems to be the price, you know, coming back from death.

And hey, it's convenient, right?
Got a new home because the old couples sympathized her, easily abducted by Hap because she didn't know what she walked into.
And when she appeared after 7 years, got back her sight as a symbol of rebirth.

I did it for me. I liked it. I was good at it. And I was really I was alive.

Yes, that all fits in as far as everything that resulted from losing her sight. But at the time Khatun said something to her like, "If you go back I'm taking your eyes to save you from seeing everything that's bad" or something like that. I'm paraphrasing, but she seemed to indicate that she was doing it for Nina's protection. I was kind of nervously waiting to see what awful things she was going to encounter that would have made blindness a better option.

What you're saying definitely makes sense in a symbolic way of rebirth when she was able to see again.

I guess the bad thing would be abducted by Hap and became an experiment object for 7 years.

I did it for me. I liked it. I was good at it. And I was really I was alive.

It could be that by losing her sight her other senses became heightened. That it was a preparation for the travel she would be experiencing. Her hearing, her smelling and her feeling (touch etc) things would then become body memories that were being stored for future use. As a whole we focus so much on our sight. We learn to pass over things that we are accustomed to and focus on diffences. Think of being in your home at night when all is still. You may hear a creak but your mind ignores it because your rationale is that it is the wind or rainwhatever. As a blind person you might also think of it directionally (where or which side that it is coming from) or in decibels. That's not by any means a total explanation. I just think Khatun wanted her to develop her mind more into the intricacies of what is around her and also be more relatable as to what the others I the set of 5 may be feeling. Just thinking. I'm by no means sold on one theory.

If you recall, when she went back with her aunt, she lived in a whore house. The babies came from the prostitues who were giving their children up.
1. She didn't SEE all the filth and lascivious nature of or misery of what surrounded her. It kept her a bit more pure.
2. She wouldn't have been chosen by Nancy if not for her blindness