Arched back, bulging eyes and walking affected is an obvious sign of pain.
You need to find out why she is in pain. If you are not experiences with diagnoses time to call a vet and get them to go over your cow..It is worth the expense especially since she is due to calve .
Exactly how soon is she due to calve and could she be in labor now?
DID HAVE A VET TO LOOK AT HER GAVE HER LA200 AND ALSO PENICILLIN SAID SHE MAY HAVE KIDNEY INFECTION BUT DID NOT SAY MUCH ABOUT THE EYES. THIS IS MY FIRST TIME TO FACE THIS PROBLEM IN A COW AND HAVE RAISED THEM FOR 30+ YRS