Yesterday I noticed that my two cows have bulging eyes. The upper eyelids look swollen too but their eyeballs appear to stick out of their heads more than usual. What ever it is, it came on sudden as they weren't like that the day before. They have no other symptoms. I've ruled out pink eye and it's not cancer eye. Flies have been bad recently but they were bad last year too and there were no bulging eyes then. They are both about to calve very soon so have been in a pen with clean ground that we recently set up in a treed area. They've been there since April 20. There are balsam, spruce and eastern white cedar in their pen. Could it be one of those trees that is causing this? Since it has affected the only two cows in there and at the same time I have to think it's the flies. Just didn't see it last year. And if it is from the flies why are their eyeballs sticking further out from their heads? Any ideas as to what else it could be? They are vaccinated for everything in the area, have water, mineral, salt, good hay. Nothings changed except the patch of ground they are on. Can't move them out but if I had an idea of what kind of vegetation is causing this I'll go pull it out.