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My dog has Horner's. Both eyes drooping? Can phenylephrine drops help?

Updated on September 23rd, 2025

Pet's info: Dog | Cavalier King Charles Spaniel | Female | spayed | 10 years and 3 months old | 19 lbs

Hello My 10yr old cavalier King Charles spaniel was diagnosed with Horners syndrome approx 6weeks ago. All has been ruled out except an MRI for tumors. My dog actually has drooping of both eyes not just one. Is this common in horners? Since I’ve read that most cases only involve one side. Will phenylephrine drops help the eye drooping and 3rd eyelid from showing?

1 Answer

Most Helpful Answer

Laura Johnson VMD

Answered By Laura Johnson VMD

Veterinarian

Published on December 13th, 2017

Hi, thanks for using Petco Pet Education Center, formerly Petcoach! Poor Lexi!

Horners can be causes by any disease process anywhere from the brain, neck, arm pit and chest. Idiopathic horners can take 4-6 months to resolve. Phenylephrine can be used in the eyes to help with the symptoms of horners. The drops can be irritating and damaging to the corneal epithelial cells so follow your Vet's instructions.

I have never seen a dog with both eyes affected and it is rare to see without other neurologic deficits. Be sure Lexi's ears were checked and consider imaging of her bulla for middle ear disease.

I hope this helps and I wish Lexi the best!
Vote Icon1Pet Parents found this answer helpful

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