severely dialated pupils unreactive to light.

Recently my cat had an issue with pupil dilation. One of her pupils was fully blown out and the other, pencil thin. Neither one reactive to light. She was moving fine and acting normal. No apparent signs of stroke, head or eye injury. This lasted hours upon hours and her behavior never indicated a serious health issue. She has vestibular disease as well and was shiwing no digns of having an episode which usually lasts under 20 minutes. What could have caused this. She is a Siamese approximately 4-5 years old.she has also had an odd fascination with licking plastic,photos,dryer sheets, insulation. Of corse I've kitty proofed the house but could this have been caused by her getting ahold of something I missed?

No reaction to light

I'm so sorry for you! My cat had the same thing for a time a while back after receiving anesthesia. I always thought it was from that, but when he needed surgery again, I mentioned it to the vet and he said it was caused by an internal infection. Once antibiotics were given it cleared up. I would definitely call your vet though and ask them about it, it is not normal, that is for sure! All the luck, and keep us posted!

There's a ton of things that could be causing it. Typically something like that in humans is a sign of brain injury. She needs to see a vet.

Often blind kitties eyes are fully dilated  like the one is, she could be loosing, or lost vision in at least one of the eyes.

Her pupils have since returned to normsl . no signs of blindness but I know what will happen if I take her to a vet. A MRI is the first thing they'll ant to do. Ive fallen into the pit twice before with my other 2 kitties and spent over 7 grand on testing to no avail. So if there's a way to problem solve without crippling myself monetarily (so long as she's not in pain) I'd rather take that avenue first.

I'm glad her eyes have returned to normal!

I know what you mean about money for pointless tests. I've done it my self (I've done tons of fecals and nothing positive in any of them).

I've just never seen that before and in humans it is a very worrying sign, otherwise I often recommend waiting before going to the vet for 24 hours.