One pupil bigger than the other after shots?

My 12 year old cat, Tweety, got her yearly shots and worming yesterday, and last night and today, she is sneezing and one of her pupils is slightly bigger than the other. They still dialate at the same rate, but the difference doesn't change when she is in different lighting. I seem to remember this happening before, but it went away soon after I noticed it, so I didn't worry about it. And she does feel puny after her shots usually, but she otherwise seems fine, and tonight is her usual self. Any ideas?

I'm not sure about pupils that are a different size but I know with humans it can mean a neurological issue, I would get ahold of your vet and get his/her take.

Suddenly different-sized pupils are a bad sign in people as Miss Mew said. Every time I have a concussion that's the first thing they check.
Mine are different-sized all the time though, oddly.
It can also be a sign of drug use, maybe the shots made her "high"?
Then again, it could be a sign of a serious side effect.

You should call the vet, or an emergency one thats open. Theyre always willing to answer questions over the phone, and tell you if you need to come in, it can wait til morning, or its fine.

The more I think about it, the more I think that the last time this happened was after her yearly shots, too. She still seems fine, and other than being hacked off that I won't let her out (she's my hunter and doesn't like to use the litterbox, hence, my wet bathroom rug -not unusual if she's mad at me ), she is still acting normally. I will continue to watch her tonight (she sleeps with me) and if it's not gone by morning I will call first thing and ask them about it. If she was acting odd and this was the first time it happened, I would be more worried . I am somewhat concerned (obviously )because I do know it is bad in people; I just didn't know if anything like this had happened to anyone else's cat, and if so, why.

Okay, just checked 2 of the other 3 cats, and one has one pupil slightly larger than the other, but not as obvious, and the third, who go an antihistamine before her shot, is normal. I'm thinking it's the shots! How odd! I think I will call them anyways in the morning and ask; maybe they all could stand an antihistamine before their shots!

Thanks, ya'll.

I would call the vet. I recall somewhere that it was to do with brain getting effected from the shots. I could be wrong. Better to consult your vet.

Thanks, I will.

This would really concern me and is something I strongly recommend you discuss with your Vet. Especially considering her nice young age of 12 , if Tweety exhibits even the slightest unusual behavior, please get her to the Dr immediately.

Found an "Ask the Expert" column from a humane society, and someone else had asked about different size pupils, and that vet said it could be nothing, or glaucoma, or catracts, or feline leukemia. Since she gets that shot every year, am pretty sure that isn't it (and the fact that she just saw the vet yesterday and her worst problem was that it is time for a teeth cleaning). I will ask my vet, I guess that would be today, now for me. Hmm...maybe it could be a reaction to the leukemia shot...Oh well, I'll let you know what they say. I've got a dr. appt. myself today, I'd better go to bed and check on her. Thanks again.

PS-Don't worry- She's my old baby, if she starts acting odd, my vet will be pulling on his/her houseshoes to make the coffee (or whatever whoever is on call does ) and be getting in the car right away !

How is she today. Anything from the vet.

Her eyes are back to normal today and the vet said that it could be a reaction to her shots, and to call back if it comes back and that they would make a note of it on her chart, and probably try an antihistamine next time and see how she does. So, everything is hunky dory I guess (at least until next time ) . Better nothin' than somethin' ! Thanks everyone