The swelling of the inside corner almost certainly indicates some sort of reaction. I’d be willing to bet he was either stung/bitten by an insect or something blew into his eye that caused the pupil to constrict. It could’ve been most anything at your work, Amy. Even a reaction to a different (or even the usual) shampoo, flea dip, perfume, etc.

I know you’re worried sick, Lord knows I would be too, but try to stay calm and keep him calm. I would imagine the prednisone should remedy the swelling by tomorrow and hopefully he’ll be just fine.

{{{{{{{{{{Hugs}}}}}}}}}}