Cats pupils

Hi, I have a 1 year old cat. The last few days one of her pupils is huge and the other one small. I can't tell if it is the way she is sitting according to the light because it comes and goes. Ive never noticed it before. She is acting ok otherwise, just a little more talking than usual. What can cause the abnormal pupils?

Thanks

[Aleda M Cheng, D.V.M., C.V.A]

Unequal pupil size is called anisocoria.  It is not normal and I would advise you to visit your veterinarian ASAP for treatment and to prevent possible blindness.  However, I cannot guarantee that the cause of your cat

[Xaviertigger]

I have an 8 month old kitten that was put on a prescription diet around 4 months of age (Purina UR St/Ox canned) due to calcium oxalates found in her urine. I was reassured by both the veterinarian and the sales representatives from Purina that this diet would be suitable for such a young kitten. After being on the diet for 2 weeks, she was found to no longer have crystals.

After about 2 1/2 months, I took her off the diet. She seems really small, compared to my other cat (3 yrs of age) and her pupils look like they are always dilated, even in a bright room. You only see a small portion of her iris around the outer rim of the pupil. She's an indoor only cat and there is no obivous wounds to her eyes. She does not keep them shut like they bother her; instead she holds open her eyes even wider than my other cat. She looks at an object like she is trying to focus in on it for long periods of time. I'm wondering if her growth might have been stunted by the calcium-restricting diet as well as possibly causing this eye "problem". She gets around the house great, but when she does go to jump up on anything, she seems to hesitate awhile trying to judge the distance.  

When I take her outside to the screened in porch, her pupils do become smaller, but they aren't the narrow slits that I see on my 3 year old cat's eyes. Besides her behavioral issues of urinating outside the litter box if it's not kept as clean as she would like it, she is a perfectly health cat. She eats both canned and dry and devours both like she's always hungry, but will stop if someone leaves the room where the food is put down.