Why are My Cat’s Eyes Always Dilated?

Cat’s eyes are one of the most beautiful eyes to see in the entire animal kingdom. And feline lovers are fortunate enough to have the privilege to look at these cuties whenever they like. But have you ever thought about what is so different about the cat’s eyes?

It is amazing to experience that cat pupil are a potential source to show how your cat is feeling — emotionally and physically. A tiny and slow blink is enough to show that your cat means to say “I love you”. But that is not enough, there can be a lot of other factors attached to it i.e., pupil dilation.

Cat’s Pupil Dilation

Cats usually dilate their pupils to improve vision. The wide and broad eyes allow cats to absorb more light, which helps in low light.

When a cat gets excited, scared, or injured, its pupils also dilate simultaneously. And it won’t last long.

Usual changes in pupil size and response to different conditions are completely normal. There is nothing to worry about, but it does promote a healthy eye function, allowing your cat to have better eyesight in different light conditions and a natural response to emotion or fear.

But if you see it continuously, and you ask yourself why are my cat’s eyes always dilated, there could be a chain of multiple possible signs. It could be because of age-related pain, over-irritation, or atrophy.

The cat’s eyes need to be dilated regularly, so if the pupils never contract, this is a real problem. So, note down all the observations carefully.

What are the Common Reasons for Pupil Dilation in a Cat?

Reason #1: Better vision

The expansion and contraction of a cat’s pupils are directly proportional to the level of light. In bright light, it mostly shrinks to protect the major part of the eye and in the dark it expands as much as it could.

If you want to know that cats can see things in the dark, its sight is not perfect and it can’t see what we see in the dark. However, it can see better in low light conditions, thanks to the dilated pupils and letting as much light into its eyes as possible.

Due to the way your cat’s pupils respond to light, your vet will generally use a bright light to assess his eye function. If you shine a flashlight on your cat’s expanded eyes and it don’t shrink, you know there is a potential problem.  Otherwise, it’s just due to better vision.

Reason # 2: Surprise or fear

If you’re panicking again that why are my cat’s eyes always dilated?

Always remember, a cat’s eyes get widen when it is surprised or frightened. It’s a natural phenomenon.

When a cat gets scared, it produces a hormone named adrenaline, which promotes the rate of survival in it. This surge in adrenaline makes them feel braver, but here’s one thing more.

It also makes changes in its bodies, such as increasing the heart rate and pumping more blood to its muscles, heart, and lungs, preparing to escape difficulties or prepare for battle.

So if your cat’s pupils are large and round, it’s best to leave it alone. It can be any noise that scares your cat, from loud noises to unfamiliar visitors, so please give it some time to settle down and realize that it is still in a safe space and approach it when its eyes return to normal.

Reason #3: Excitement

If the cat’s eyes enlarge when it’s playing – it’s pretty confusing. Is it afraid of the cat toys or you?

This question often confuses the caretaker, but dilated pupils may also be a sign of excitement. However, you can easily distinguish the difference between the two by observing the surrounding environment.

If you are playing with your cat or just giving it snacks, you can safely assume that its pupils are dilated due to excitement. However, if it hides under your sofa in a storm, it may be scared.

Here is the same reason again as mentioned above, that cat’s eyes dilate while playing is the adrenaline is pumped through their bodies again. How we play games with cats is the same as what these animals do hunting in the wild. It needs to be alert, fearless, and have enough blood in its muscles so that it can react quickly and grab the next meal, and for this, it rely on adrenaline.  So, here it connects the two of it like playing with toy mice, chasing ropes, or kicking cat toys at it. Therefore, when it play, an adrenaline rush hits them.

But, what if your cat’s eyes are always widened?

If your cat’s pupils dilate periodically and the light around her changes, this is normal, and there is no need to worry. Your cat may suffer from it having its tail stepped on or by a loud noise.

Like there’s also another reason that the brighter the light, the clearer cats can see. According to research, cat pupils are 10 times larger than human pupils. If the light is bright enough, most probably the cat may dilate its pupils for multiple reasons. And at night, it’s usually due to darkness. And we assume this to be a massive problem.

Only when you notice that your cat’s pupils are dilating all the time, you should worry about it and check it to make sure your cat’s eyes are healthy.

One of the most common reasons behind it is Continuous expansion. It is usually a sign of high blood pressure, but it may also indicate that they are blind, experiencing chronic pain, or have other underlying health conditions.

Some other medical or psychological reasons include Shock, Excitement, Pain, Unwellness, Eye trauma, etc.

My cat’s eyes keep dilating more often – Why?

Mostly cat’s eyes should remain neutral most of the day. Due to medical or psychological reasons, the cat’s eyes may remain dilated during the day and night. Common explanations include:

  • Blindness
  • Stress & Anxiety
  • Overexcitement
  • Chronic Pain/ Disease
  • Intake of Toxins
  • High Blood Pressure
  • Dysautonomia
  • Iris Atrophy
  • Ocular Cancers and Tumors
  • Eye infections and diseases
  • Feline Leukemia Syndrome (FeLV)

Let’s discuss them one by one.

1.BlindnessSigns of cat's blindness leading to dilation
It can be temporary or permanent. In addition to expanding pupils, signs of cat blindness include:
• Clumsy and collision with unfamiliar objects.
• Scared while jumping or climbing
• Getting frightened randomly with the sudden attacking noises
• Facing difficulty in judging and locating the water source.
• An excessive pitch of voice, and increasing pain when not responding.
How to deal with this situation?
Don't panic. Compared to sight, cats rely more on smell, hearing, and touch.
Make some rearrangements in your home to make it easier for your cat to roam around, so it can quickly adapt itself to poor or no vision.
You should provide unobstructed access to food, water, and garbage.
Kick your presence when entering the room.
Talk to your cat regularly because your voice will provide comfort.
Pro Tip: A simple test to test if your cat’s vision leading to dilation
Shake a ball of yarn in front of the cat’s eyes. Don't swing the yarn very close to the cat’s face as the cat may feel it.
If your cat can see properly, its hunting instinct will start working.
It’s evident that a blind cat will behave differently. Moreover, if your cat has completely lost its vision, it will learn to cope.
2.Stress and AnxietyWhat to do if you notice that your cat is suffering from stress and anxiety/ exhibits other symptoms of stress?
Another reason for the dilation in some cats is that they are scared because when they feel anxious, worried, or hear a sudden loud noise, their eyes will naturally expand.
Continued high stress can cause several other problems, including aggression or loss of appetite.
It's important to take the following steps to eradicate and treat dilation in cat's pupils
• Try to find out the core reason, like any new changes in your daily life. Plus, are there any new people or animals in your family? Make necessary adjustments accordingly.
• You can try to bring your cat to a new environment to make him more comfortable. In addition, be sure to add a lot of hiding places for your cat at home, such as cat carts or cardboard boxes. If your cat is stressed and needs some time, this provides a place to retreat.
• If your cat already behaves nervously, medication can help them calm and relax. If the treatment is effective, you will notice that the cat’s pupils shrink.
• Maintain a strict and proper schedule for daily activities to keep your cat busy, happy, and contented.
3.OverexcitementReasons of Overexcitement
If nervousness or being scared isn’t the reason for your cat’s pupil dilation - it may just be overexcitement.
• Cats get excited about numerous reasons. If you don't calm them down, they may become overly excited. It may result in extra pressure on their heart.
• When a cat is in a new environment, overexcitement is common.
How to treat it?
For some days guide him to a separate room. Once the cat returns to its normal state, its pupils will be ok.
4.Chronic pain/ diseaseSymptoms of eye dilation due to chronic pain
One of the most common reasons for pupil dilation in a cat is chronic pain. Cats try to hide their pain intentionally. It is because vulnerability in the wild will make them a target for predators.
• Cat loses its appetite.
• It behaves more aggressively or tiredly than usual.
• It loses interest in self-grooming.
• It may be suffering from arthritis or dental problems.
For the best advice, consult a vet. Then they will be able to diagnose what is causing your cat's continued discomfort.
Cats can hide their body pain very well, but not all the time. The expanding cat's eyes are clues. If your cat's eyes are wide open, look for other symptoms as mentioned above.
5.Intake of toxinsSymptoms of dilation through intake of toxins
It leads to dilated eyes in cats. Cats that eat toxins will have enlarged eyes.It may include the following risks:
• Vomiting and diarrhea
• Difficulty breathing
• Weakness and lethargy
• Muscle tremors
• Low body temperature
• Lethargy
• Loss of appetite
Most of the household products contain toxic. When your cat ingests toxins, it needs to get rid of them from the body.
6.High Blood pressureSymptoms of High Blood pressure
160/80 mmHg, is considered to be high blood pressure in cats. Older cats suffer more of it. And it can easily be recognized through the pain lying in their eyes resulting in dilation.Hypertension or high blood pressure doesn't come suddenly. Other health problems like kidney issues or heart problems are relevant with it.
Other symptoms related to it include Excessive alcohol consumption, Blood in urine, Nosebleed.
How to treat it?
It may be hard for vets to diagnose hypertension and abnormalities in cats’ imaginative being. In that case, consulting an experienced vet is the only prescribed solution.
7.DysautonomiaSymptoms of Dysautonomia
Dysautonomia, additionally referred to as Key-Gaskell Syndrome or Feline Dilated Pupil Syndrome assaults a cat’s automatic nervous machine (ANS).
• Digestive problems
• Lack of appetite
• Unusual weight loss
• The constant urge for food
• Slow heart rate
• Dry nose
• Low body temperature
• Not being to urinate or defecate
• Enlarged esophagus
• Swollen abdomen
You must take your cat to the vet immediately if you see any of these symptoms. In most cases, the cats don't survive with these symptoms and usually, only the medication is provided. It takes almost a year to recover fully, and many of the times permanent dysfunctionality remains at its place.
8.Iris AtrophyAfter-effects of Iris Atrophy
It's a common phenomenon in most cats that their iris starts getting thin as the cat grows older and results in dilation.Its permanent damage that’s why it’s irreversible, but it will not suffer any pain in this. Some major changes after it include sensitivity to luminous light, though. Moreover, it will squint and hide in dark corners, so better to avoid it.
9.Ocular Cancers and TumorsSymptoms of Ocular Cancers and Tumors
A malignant tumor is developed at the back of the cat’s eye sometimes. It can spread to other parts of the body as well and it’s extremely painful for the cat, leading to dilated pupils.
• Discoloration
• Inflammation
• Glaucoma
• Irregular discharge from the eye
• Misshapen iris
• Cloudy eyes

The diagnosis of eye tumors is not an easy task, but an ophthalmoscope is used. Moreover, Biopsies are done to judge its severity. If the tumor is small, the laser is used to treat it. Or if the case is worse than this, full removal of the eye will be needed to prevent the tumor from spreading.
10.Eye infections and diseasesTreatment of Eye infections and diseases
Cats easily get caught with severe eye infections and diseases. It may have several reasons behind it like bacteria, irritation, or allergies.Simple eye infections can be treated with some dosage of antibacterial eye drops. If it works then, your cat's eyes will return to their original size.
11.Feline Leukemia Syndrome (FeLV)Symptoms of (FeLV)
This condition can cause the irregular corners of the eyes to move from one eye to the other. If the change in an uneven eye pattern is notice regularly, the cat most probably is suffering from FeLV.
It’s an infectious disease that can easily be transmitted through blood, saliva, or waste. Many of the times, its severe causes can lead to death. FeLV vaccine is a must for all adult kittens and cats.

• High fever
• Shortness of breath
• Loss of appetite and weight loss
• Pale gums
• Infertility
• Lethargy
• Poor hair quality
FeLV cannot be cured, so vaccination is essential. It’s better to keep the cat indoors in such a case. It is because Co-breeding is a risky option to have here as the infected cat again catches the virus.

What if only one eye of my cat suffers from dilation?

This question is much confusing than why are cat’s eyes are always dilated. A mismatched cat pupil size means that your cat’s pupils are not the same. It may have several reasons behind it for the real cause. Permanent dilation of one eye is more common, so your cat can keep one eye closed. [H2]Common reasons include:

  • Physical trauma
  • Glaucoma
  • Corneal ulcer
  • Ectopic disease – common in old cats
  • Anisocoria

Like double pupils, uneven eye corners are a long-term condition. In contrast, trauma, like a punctured eye, can cause a temporary disparity in the pupil. If heterotopic pupils last longer than 24 hours, your cat should be checked by a veterinarian.

Final Words

Pupils that dilate and constrict in every other situation is a healthy sign, but if it remains permanent then it can be concerning. It is best to judge the cats’ eyes often as it says a lot about how your cat is feeling and maybe you can judge the underlying conditions from it.

Go to your vet at first if you notice your cat has permanently dilated pupils. Only a vet can diagnose the underlying problem and provide effective treatment for it. Other conditions could also be the culprit, and you can manage the majority of it with the correct treatment.

The most important thing to remember is not to panic. Follow the advice of your vet and your cat will likely be well and back to normal in no time at all.


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