rat urine/ burning of human eyes

Question
Do you know if pet rats urine can cause eye burning and eye pain in humans.  My daughter has had pet rats for a couple of years and she has two males I believe.  She cleans the cages maybe every week or so and man do they stick and she will (Ive noticed she will leave the the cage droppings for lack of better word in the room) they are not spayed or neutered. she got them from pet store 1 rat just had about 11 babies and ate them all. Gross. she cuddles them often but I dont hold them I have pet them but its been awile..
Thanks Laurie

Answer
 Rat urine, just like the urine of most species, contains ammonia which can burn and irritate eyes, not only of you but of your rats as well, which is why it is important to keep the cage cleaned frequently.  Males have a much stronger odor than females, and tend to pee all over the cage rather than in the corners so the odors can get even worse.  Neutering can help them stop marking and slightly reduce their scent.  Other than that I would recommend changing their bedding, maybe even using a combination of two, to try to cut down on the smell.  Also, when your daughter cleans the cage make sure she washes all the sides, the levels, hammocks, toys, and even the ceiling as well as the litter pan, as odors can get onto pretty much anything in the cage and if she is only dumping the litter pan it won't get rid of the smell on the rest of the cage.  I like to put the cage (minus litter of course) in the shower and let super hot water run over it for a while before wiping it down with a cloth or brush.  Any toys that can't be washed should be thrown out once they get peed on and hammocks can usually be washed in the machine or handwashed in the sink.  I hope that helps answer your question, good luck with your rats!