A,Nervous,Black,Shorthair,Cat,With,Huge,Eyes,And,Dilated

Why Do Cats’ Eyes Dilate | Everything You Need to Know

Katelyn Son
By Katelyn Son
Medically reviewed by Ivana Crnec, DVM
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What Do Dilated Cat’s Eyes Look Like?

what do dilated cat eyes look like

Cats have vertical pupil slits that dilate and constrict in different situations. The iris is the colored part of the eye that ranges in color from greenish-yellow to gold. The pupil is the black part of the eye that is essential for controlling the amount of light that enters the eye.

When a cat’s eyes are dilated, the pupil, which is usually a vertical slit, will expand and appear fully round. Its eyes will also seem to be bigger. The roundness of the pupil will make it look similar to the roundness of human pupils.

Is It Normal for a Cat’s Eyes to Dilate?

Yes, like how the eyes of human beings dilate when there is a difference in ambient light levels, it is also normal for a cat’s eyes to dilate and change pupil size due to bright light and low light.

When a cat’s eyes are dilated, it usually controls the amount of light that enters its eyes. The more dilated a cat’s eyes are, the more light enters the eyes, hence better vision in dim light and in dark environments.

However, various other reasons cause pupil dilation in cats. In normal situations, a cat’s eyes will dilate for a short period as a response to different conditions. Although it should be noted that when the pupils remain dilated for an extended amount of time, it could be a sign that the cat may have some health problems.

In cases when the pupils are persistently dilated, the cat should be taken to the veterinarian for a physical examination. Dilated pupils could signify that the cat is terrified and may be experiencing some pain.

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What does it Mean When a Cat’s Eyes are Dilated? 

Wondering why do cats’ eyes dilate? A cat’s eyes are a great communicator of emotions. A cat’s eye can be dilated because of these common reasons:

  • Environmental Factors. When a cat’s eyes are dilated due to environmental factors, it is usually when the visibility or light levels are low. So when a cat is in the dark or in dim lighting, a cat’s eyes will naturally be more dilated than during the daytime.
  • Excitement. When a domestic cat is chasing around the room after a toy, it becomes excited, and usually, an excited cat will cause its pupils to dilate as it is in a playful mood. Likewise, when a curious dog confronts a cat, the cat may feel like it’s in danger. This will cause its pupils to dilate because of fear.
  • Danger. If the cat feels afraid and alert with the fur on its tail standing up, it can mean that the cat senses danger and is in fear. This will cause the affected eye to dilate for a short amount of time. This is perfectly normal, and the large pupils will return to their relaxed state once the cat is more settled down and calm.
  • Health Problems. In other cases where an older cat’s eyes are constantly dilated for a long time and not caused by the conditions mentioned, it could be a sign of an underlying health problem. The cat should be taken to the veterinarian for a check-up for immediate pet care.

Should You Look a Cat in the Eyes?

No, a cat owner should never look at their cats directly in the eyes as cats are known to interpret staring as an act of aggression, intimidation, and rivalry. Rival cats do not always resort to violence at first.

Instead, they try to stare at each other, and if the other cat looks away first, it will be considered a surrender. It is commonly known to most cat owners that when looking directly at their cat, they should focus on their body language. Slow blink or wink, as cats will take this as a sign of affection.

Although the fact is that showing your cat the sleepy eyes will make them realize that the owner is not a threat. It is also evident that cats are likelier to go toward a person who is not fond of them than toward a person who loves cats.

This is because a person who is not fond of cats will never look directly at a cat and cats find this non-threatening. However, a person who loves cats will try to get the cat’s attention by calling and looking directly at the cat, which it can find intimidating and uncomfortable.

Should I be Worried If My Cat’s Eyes are Dilated for a Long Time?

Should I be Worried If My Cat’s Eyes are Dilated for a Long Time

Yes, if a cat’s pupils are dilated for a long time, it is important to find out why.

A cat with persistently dilated or unevenly dilated pupils (pupils of different sizes) should be taken to the vet to get immediate medical attention, especially if other symptoms accompany it. Dilated pupils could signify an underlying cause like eye problems, infectious disease, trauma, or cancer. Some of the related underlying diseases are:

  • Progressive Retinal Atrophy (PRA): When the cells in a cat’s eyes weaken over time and can even lead to blindness.
  • Glaucoma: Increased intraocular pressure results in wide pupils. It can affect one or both eyes and requires immediate veterinary attention.
  • Iris Atrophy: Thinning of the iris that appears as if there are holes in the iris structure. Usually, it affects only one eye (unilateral).
  • Ocular Tumors: Tumors affecting the eye structures can trigger wide pupils. Based on the type of tumor, other signs are chronic pain, third eyelid changes, eye discharge, and cloudy eyes.
  • Anisocoria: Anisocoria is when the cat has uneven pupils or where one pupil is more dilated than the other. Anisocoria can be the result of corneal ulcers and glaucoma.
  • Poor Vision: With age and other underlying conditions, a cat’s vision can deteriorate, leading to dilated pupils. A cat with poor vision is likely to squint a lot.
  • Feline Dysautonomia: A neurological condition that affects the autonomic nervous system and results in dilated pupils and respiratory symptom.
  • Infectious Diseases: Feline Leukemia (FeLV) and Feline Herpesvirus can also cause a cat’s pupils to dilate.
  • Hypertension: High blood pressure (hypertension) can cause dilated pupils and symptoms such as weight loss, appetite changes, and poor coat quality.
  • Systemic Issues: Certain systemic diseases can also cause dilated pupils. Such an example would be kidney disease followed by kidney failure.
  • Toxicity: Ingestion of certain toxins can also cause the cat’s eyes to dilate. Common toxins for cats are human foods & drugs, plants, and household chemicals.

Do Cats’ Eyes Dilate When Dying?

Yes, a cat’s eyes can dilate when a cat is dying or after a cat has died. This eye dilation is a response to an increased heart rate and elevated blood pressure, immediately before death.