Green discharge in eye

One of the colts I look after has a greenish/yellowish discharge coming out of his eyes. Mostly just one eye but the other has some too. He doesn't seem to have any in his nose so I don't know if it would be a cold. Do you know what would cause this and how serious it might be? - Thanks!

This could be anything from an allergy to a viral infection. It would be a good idea to check his temperature morning and night, monitor his activity levels and appetite and contact the vet if anything looks "off".

FYI If it had been just one eye with a discharge, I would have said rinse it with plain saline like for contact wearers and see if it improves in a couple of hours. If not then get the vet out as damage to the eyes can lead to serious consequences in just a few days.

His appetite is normal but he seems a bit more lethargic than usual. I'll try the saline in his eyes and if he doesn't seem better I'll try to get a vet out to check him out. Thanks!