Cats Eyes Always Fully Dilated. If you have a cat with one dilated and one is not, there are a number of things that could be wrong. Our zebulon's pupils never close to a slit like normal cat's pupils do in bright light.
If you notice changes in your cat's iris or the appearance of splotches of other colors, contact your vet. Dilated pupils are pupils that are larger than normal in size. Apparently it's fairly common in fiv cats.
While cats don't generally suffer from the type of allergies that result in itchy, watery eyes, irritants in their environment can produce a similar effect.
My fiv boy is totally blind. But occasional dilation can be caused by contentment, excitement, and most often the level of light in her surroundings. In bright light, your pupils constrict (get smaller) to prevent too much light from entering your eyes. Our zebulon's pupils never close to a slit like normal cat's pupils do in bright light.