I have a young Flemish who has had a mildly irritated eye for a while now too. It started right after she got her eyes open (she's about 12 weeks now) and I started using an NFZ Puffer on it, and that helped, but as soon as I stopped using it the gunk came back. I don't think this can be anything contagious, she is still in the same cage as her sisters and none of them have ever shown any sign of it.
I thought it was probably a lingering infection of some sort. I wanted to try the Terramyacin ointment on it, but all of the two or three stores here in town that carry the stuff were back ordered on it, and hadn't been able to get any in almost a month.
Right now, it is just very slightly goopy, not enough to impair her vision or anything. It doesn't seem to bother her, she acts normal.