Horner’s Syndrome

Horner's syndrome is a pet health condition that occurs when there is damage to the sympathetic nerve pathway to the eye. When this happens, various facial muscles do not become stimulated as they should. This damage can have many different causes on pets and will occur anywhere along the nerve's pathway to the eye.

Horner’s Syndrome

How it Affects your pet

When something blocks the sympathetic impulses to your pet's eye, the parasympathetic supply becomes overbalanced. As a result, your pet's pupil constricts and the muscles surrounding the eye relax. The eye then sinks into the socket and the third eyelid becomes prominent. Finally, the upper eyelid droops.

Common symptoms

There are several symptoms of Horner's syndrome that you can look for, and they typically occur on the side of the face that has been injured. However, if your pet's condition is idiopathic, it can occur on either side. It is interesting to note though, that felines do not develop idiopathic Horner's syndrome: Eye That is Sunken into its Socket, Small Pupil, Drooping Upper Eyelid, Prominant Third Eyelid, Dilated Blood Vessels on Affected Side of the Face, Warmth on the Side of the Affected Eye, Sweating on the Side of the Affected Eye (Horses).

Treatments

If it is determined that your pet has idiopathic Horner's syndrome, it will typically recover on its own in about three to four months. Your veterinarian can help the condition temporarily however, by prescribing phenylephrine eye drops to be used two to three times per day. If your dog or cat's condition is determined to be due to an injury, the underlying cause will need to be treated first. This may involve antibiotics, sutures, surgery or a wide variety of other treatments depending on the problem. Once your veterinarian has treated the cause, phenylephrine eye drops are recommended to relieve clinical symptoms of the eye.

Breeds Affected

Horner's syndrome can occur in many different animals, especially cats, dogs and horses. 40 to 50 % of animals that are affected by this condition are diagnosed with an idiopathic form of the problem. Since horner's syndrome can also occur due to injuries or illness, any breed of dog, cat or horse can be affected. However, the following breeds of canines are most vulnerable to Horner's Syndrome: Golden Retrievers and Cocker Spaniels.

Horner’s Syndrome Affects

  • When something blocks the sympathetic impulses to your pet's eye, the parasympathetic supply becomes overbalanced. As a result, your pet's pupil constricts and the muscles surrounding the eye relax. The eye then sinks into the socket and the third eyelid becomes prominent. Finally, the upper eyelid droops.

Similar conditions

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