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My cat's pupils are different sizes. Should I call the vet right away?

Updated On September 23rd, 2025

Pet's info: Cat | Mixed Breed | Male | neutered | 2 years old

My cats pupils are dilated to different sizes. Should I be concerned?

5 Answers

Most Helpful Answer

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Answered By Angel Alvarado, LVT

Licensed Veterinary Technician

Published on May 31st, 2016

Yes, unequal pupil sizes can indicate trauma or neurological disease. Schedule an exam with your veterinarian today or tomorrow at the latest. Monitor for ataxia (wobbly gait), weakness, lethargy or head tilting.

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8Pet Parents found this answer helpful

Other Answers

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    Answered By Lindsey Edwards MVB, BSc, IVCA

    Veterinarian

    Published on

    If one is fixed open and the other is very small this sounds like Horners syndrome which occurs from swelling or pressure on the nerves in the head and neck. Although the cause cannot always be identified (and some cases improve over time), trauma, abscesses and growths can all contribute to such signs and investigation and treatment can improve recovery.

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    5Pet Parents found this answer helpful

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    Answered By Angel Alvarado, LVT

    Licensed Veterinary Technician

    Published on November 20th, 2016

    Have Nathan examined by your veterinarian. Unequal pupil sizes can be due to head trauma, infection or neurologic conditions. Monitor for other signs such as lethargy, wobbly gait, or bumping into objects.

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    1Pet Parents found this answer helpful

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    Answered By Dr. Strydom, DVM

    Veterinarian

    Published on March 30th, 2018

    Hello, thank you for using Petco Pet Education Center, formerly Petcoach. Unequal pupil size is called anisocoria. I don't think I would be concerned unless she is showing other symptoms of illness (like seizures, incoordination, etc). I would be more concerned if this was a new problem vs. her having it her whole life. I suggest you just monitor Aria for now and point out the anisocoria to the vet at her next exam. They can use a special eye scope to check the eye. Hope this helps. Best wishes.

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    Answered By Dr. Melanie, BVSc MS

    Veterinarian

    Published on November 25th, 2016

    This is a condition called anisocoria. This can be caused by head trauma, corneal injury such as an ulcer, glaucoma, or injury to the nerves that run to the eye. This is a medical emergency when this suddenly appears, and Emmy needs to see a vet right away. I would take her into a vet now. The vet can diagnose what is causing the anisocoria, and can treat accordingly.

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