Can a corneal transplant cause death?

Not in the hospital, cleanliness is key and they wouldn't let any infection take hold.

It MIGHT cause death if the person couldn't see well enough to cross the road safely and was hit by a car.

An infection can occur and end up being lethal, it's really rare but possible.

If this blind person is under anesthesia, like they get put to sleep for that they could die, it's a very real possibility and it does happen but it isn't likely to happen. The percentage of it happening is like the same percentage of girls who get prenant with an IUD in. Like 0.9%. You'd be better off giving them the ability to see and then killing them off in something more likely. Like when they are experiencing the vibrant colours of the wirkd for the first time in a long time they don't pay attention and then they get hit by a car and die in the hospital bed surrounded by the people they love. Makes it a sad story.