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Ask Dr. Michael Salkin Your Own Question
Dr. Michael Salkin
Dr. Michael Salkin, Veterinarian
Category: Cat Veterinary
Satisfied Customers: 30418
Experience:  University of California at Davis graduate veterinarian with 45 years of experience.
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I woke up on sunday with my cats pupil enlarged. I took m to

Customer Question

I woke up on sunday with my cats pupil enlarged. I took him to the vet yesterday they tested him for Glaucoma and Uvitis. The pressure in the large pupil eye was higher than the normal eye, but below glaucoma reading. He is being treated for possible units with oral antibiotic. He seems a little more himself today but I don't see any difference in the pupil. He is being pretty clingy and just wants to sit on the couch. he is eating, drinking and using the bathroom. Lungs and heart were good. Just not sure this is correct I am wondering if he should be on eyedrops or something.
Submitted: 2 years ago.
Category: Cat Veterinary
Expert:  Dr. Michael Salkin replied 2 years ago.

Please clarify "He is being treated for possible "units".

Customer: replied 2 years ago.
Uvitis I am sorry that might not be correct spelling
Expert:  Dr. Michael Salkin replied 2 years ago.

Thank you. I'm a bit puzzled. Uveitis - inflammation of the iris and its attachments - should cause a miotic (smaller than normal) pupil not a mydriatic (larger than normal) pupil. Did the vet think that the eye with the smaller pupil was the abnormal eye?

Customer: replied 2 years ago.
No. I am sorry let me clarify - apologize we have had several sick animals and its all running together. The eye with the enlarged pupil is the sick eye. They tested it for glaucoma and I though uvitis but maybe they said something else. it came back with a higher pressure than the normal eye but below glaucoma. I want to say it was "27" and glaucoma was "30. Kitty also had some gunk in his ear, and has been pawing at the ear so they thought he might have a middle ear infection they did see some crusty gunk.. They did sedate him and look in the eye and did not see anything abnormal (other than dialated pupil). His eyelid looks a titch swollen but not much. They are treating him with antibiotic for "possible" infection. Supposed to follow up in 7 - 10 days. We started the antibiotic yesterday.
Expert:  Dr. Michael Salkin replied 2 years ago.

Thank you. To confound things further, it's possible for a glaucomatous eye to also suffer from uveitis. A specialist veterinary ophthalmologist (please see here: should be considered when initial testing isn't confirmatory. Playing devil's advocate, I must tell you that middle ear inflammation (causing a Horner's syndrome) will cause a miotic (smaller than normal) pupil - not a mydriatic one (larger than normal). I'm going to post my synopsis of anisocoria (unequal pupil size) for you. There are quite a few considerations - some serious, some innocuous...

The two most common causes of anisocoria are the feline leukemia virus (FeLV) and the spastic pupil syndrome - a condition unique to cats in which owners report anisocoria which may sometimes be transient and independent of ambient light levels. Clinically, cats with this syndrome appear to be healthy, are visual, and have no ocular abnormalities beside unusual behavior of the pupils. Unfortunately, most affected cats test positive for FeLV at the initial presentation but not all which confounds the diagnosis.

Anisocoria also results from primary iridal (iris) disease (uveitis)- any inflammatory process causing miosis (an abnormally small pupil); and primary neurologic disorders involving cranial nerve III and Horner's syndrome (as mentioned above in association with middle ear inflammation).

The initial database should involve testing for FeLV and a complete ophthalmic examination including menace response, dazzle, palpebral, pupillary light, and vestibulo-ocular reflexes. Fluoroscein staining of the cornea should be performed looking for corneal trauma and intraocular pressure should be measured (the elevated pressure of glaucoma will enlarge the pupil (mydriasis) and the lowered pressures of uveitis will make the pupil miotic).

Much of the above is beyond the capability of many generalist vets so his vet may recommend referral to a board certified veterinary ophthalmologist. Please see here:

Please respond with further questions or concerns if you wish.

Expert:  Dr. Michael Salkin replied 2 years ago.
I'm just following up on our conversation about your pet. How is everything going?
Dr. Michael Salkin