If you have NORMAL SALINE (NaCal 0.9%) plain simple eye drops with nothing else in them, you can use a drop or 2 in the irritated eye to offer some relief to the rabbit until it can be examined.
its milky colored? Like white? My bunny had a bunch of white goop in her eyes and I took here right into the vet that day. They gave me some antibiotic drops for her, and within a day or two it cleared right up. Now this however was more gloopy then runny. I'm so sure about runny.
You may want to have this moved into the infirmatory, where you might get more replys