Hey rasmus,
I have never experienced anything like you have described. Perhaps she got some sand or other debris lodged in there. Perhaps several daily mistings may help it clear up? Does she have any mucous around the mouth or nostrils? Sometimes a respiratory ailment may cause the eyes to get crusty and close shut. I don't have the slightest clue... If it doesn't appear to be infected, I wouldn't worry about it for now; maybe try misting the cage to increase humidity...and see how that goes. It can't hurt....
On a side note; a couple of months ago, I noticed that my male macraei was favoring one of his eyes, keeping it closed for long periods of time.. One day while cleaning their enclosure, I was able to approach him, which was very odd, for he would normally run away when he saw me. I then realized that he is blind in the one eye that he was favoring.. I guess it doesn't seem to bother him; he has no other health complications, and has even been breeding my female. He has since stopped holding his eye closed, but still lacks the eyesight from that eye... If his eye ever becomes infected, or abnormal, depending on its severity, I would probably take him to the vet... This doesn't seem the case with your girl..
If it doesn't appear to be infected, I would give it time, and perhaps the increased humidity would help it open back up..
This is by no means what you should do...for I have not physically seen your animal, nor have I ever experienced something like that...If it was in my collection, I would probably do the misting thing... so I guess you can take this for whatever its worth... Take care,
bob