Is it expensive to go to Seoul to get a cataract surgery?

I've been seriously considering going to Korea for the past few months to have my eyes done. There are options for getting them done in Mongolia, but looking at the latest figures online, it seems like the ones in Seoul are better. But the cost of the flight, the length of time you have to stay in the hospital, and the possibility of having to go back and see a doctor after you get home are all a concern.

Do you have any experience? Was it really expensive to have your eyes done abroad? How many days were you in Seoul at the time? I'm having a hard time making this decision right now, because it seems like there are so many options.

If anyone knows Merhi well or has had previous experiences, I'd love to hear from you! Not just how the surgery went, but what it was like, who you were able to contact after you got home, and all that.