“Droopy eye” is a condition in which the nerves to a dog’s eye have been inflamed or damaged, and may be a sign of what is called 'Horner's syndrome'. First, the dog’s upper eyelid may appear to droop or not fully open. The pupil may be very small and unable to open in response to lowered lighting. Finally, the “3rd eyelid” or nictitating membrane located inside the lower eyelid may appear inflamed or push out, leaving a reddened area above the lower eyelid. This syndrome indicates a lack of nervous system communication and may reflect a deeper problem, especially if your dog is having difficulty walking or swallowing. However, in breeds like Golden Retrievers, Horner’s syndrome may present idiopathically, that is, without any identifiable cause. While somewhat unsightly, Horner’s syndrome on its own may not present a serious risk for your pet.

If you notice your pet’s eye exhibiting the above signs, you will need to see a veterinarian to make sure there are no associated conditions causing Horner’s syndrome. The veterinarian will want a history of any activities your dog has engaged in that might result in injury, and any observations you may have of abnormal behavior in your dog. Tell your veterinarian if your dog has recently had a tumor or any surgery.

The veterinarian will perform a number of routine tests, usually an analysis of a urine sample, a CBC (an analysis of a blood sample to count the types of cells and their relative proportions), and of course a physical exam. These tests will help the veterinarian to determine the underlying cause, if any, of the droopy eye.

If the veterinarian suspects a tumor, broken bone or injury, medical imaging will be needed. X-ray and ultrasound are useful for showing some types of injury, and can usually be done quickly in a vet’s office. MRI and CT scans require a larger machine, and so your vet may refer you to an animal hospital that has the equipment.

Finally, if your dog has presented with a fever along with abnormal behavior, your doctor may conduct a spinal tap. This involves shaving and sterilizing an area on your dog’s back, and inserting a needle between the vertebrae to collect spinal fluid. An analysis of this fluid will aid the veterinarian in determining if your pet has an infection of the nervous system like meningitis.

The acute signs of droopy eye might be treated with eye drops. However, if there is an underlying cause, this will need to be treated according to the type of ailment. Spinal infections like bacterial meningitis will need quick administration of lifesaving antibiotics, whereas tumors will need surgical removal, radiation or chemotherapy. In the case of trauma (e.g. car accident, fall etc.), surgical intervention may be required to free pinched or trapped nerves and reduce scar tissue.

Idiopathic droopy eye may sometimes resolve on its own, but to ensure complete recovery, veterinarians often recommend medications of some type. These will need to be administered every 12-24 hours for about three weeks. The outlook for idiopathic Horner’s is typically good. The condition may re-appear in cases of dehydration or infection, but is not considered serious and can be treated the same way.

The outlook of other conditions with Horner’s syndrome as a sign will vary, but in general, the droopy eye portion can be resolved the same way, and the underlying cause treated according to a veterinarian’s recommendation.

Horner’s syndrome can be expensive to treat. To avoid high vet care expenses, secure pet health insurance today. The sooner you insure your pet, the more protection you’ll have from unexpected vet costs.