My cat has dilated pupils: 3 possible reasons


Cats have the particularity of being able to modify the shape of their pupils according to the ambient light, their mood or their state of health. So when they glare at us, that is, when their pupils are dilated, it’s for a good reason! Find out in this article whether there is reason to worry or not!

Good to know: the size of a human’s pupils can be multiplied by 15 compared to their smallest size. As for the cat, the size of its pupils can be multiplied by 135!


1. It’s dark

If the area your cat is in doesn’t have a lot of light, it’s normal for their pupils to widen. Indeed, this dilation allows it to better capture the light. And therefore to see better in the dark! Note that in total darkness, your feline cannot see anything, just like you. On the other hand, if there is even a tiny source of light (candle, moon, star…), it sees there as in broad daylight!

Being able to expand and reduce the amount of light entering their eyes is absolutely vital for our feline friends. And for good reason, without that, they would not be the formidable nocturnal hunters that we know.


2. It is excited

If your cat is excitedscared, angry, or startled by a sound or movement, their pupils may suddenly dilate. For example if it plans to attack your ankles, their pupils will widen. In this case, don’t worry, they should return to their initial shape once the strong emotion has passed.

A cuddling session or approaching mealtime can also trigger your feline’s pupils to dilate. This then means that the latter is happy and satisfied.


3. It is sick

Does your cat have constantly dilated pupils? It is not normal. Even a hyperactive, and therefore always excited, cat should narrow its pupils from time to time. Therefore, a visit to the vet is in order.

Several health issues can cause your cat’s pupils to become permanently dilated. But the most common are Key-Gaskell syndrome and hypertension. In this case, in addition to having permanently dilated pupils, the animal also presents other unusual symptoms: weight loss or gain, loss of appetite, excessive thirst, difficulty urinating, vomiting, etc.

Poisoning from a poisonous plant, medicine, or the bite of a venomous animal can also cause the pupils to dilate constantly. Just like a chronic disease, such as arthritis, a permanent source of pain and discomfort.

Also note that if your cat’s pupils are different, i.e. if one is dilated and the other is not, this is also a sign of a medical problem. Indeed, this symptom is called anisocoria, and leukemia, retinal disease, cancer, injury or even glaucoma can be the cause.


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