What you see. The starting point for addressing any equine health related issue is your observation.


Eye is Tearing or Watering (in Adult)


Lacrimation, (tear production) is a constant process and functions to clean, moisten and lubricate the eye. Tears are produced by glands within the eyelids called lacrimal glands. Drainage of tears normally happens through a duct called the naso-lacrimal duct, that empties through a tiny hole in the wall of the nostril.

Increased tear production is a natural response to irritation on the surface of the eye or within the conjunctival sac, the membranes which enclose all but the clear front of the eye. As such, tearing is a sign of almost any problem associated with the eye or surrounding tissues. Dust, wind, and flies are among the common irritant causes.

Tearing can also be caused by a blockage of the outflow tube (the naso-lacrimal duct). Tearing is also a response to pain, it is commonly seen in inflammatory conditions like Equine Recurrent Uveitis (ERU) or Moon Blindness.

  • Code Red

    Call Your Vet Immediately, Even Outside Business Hours
    • If this problem seems severe and has come on suddenly.
    • Most eye problems are considered veterinary emergencies.
  • Code Orange

    Call Your Vet at Their First Available Office Hours
    • If the eye appears otherwise normal.
    • The eye does not seem painful and the horse does not seem distressed.
You also might be observing
Very Common
Less Common
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your role


What To Do

Assess your horse's eyes carefully. Look especially for grayness or any erosions in the clear surface of the eye (the cornea). Look for environmental causes such as dust, wind or flies. Manage those things as well as you can.

Place a fly mask, and control flies. It is safe to rinse eyes with saline if you feel confident doing so. Look for other signs of eye problems. Recognize that eye problems can worsen rapidly and be prepared to consult your vet if tearing continues.

What Not To Do

Do not apply steroid containing ophthalmic ointments or drops without vet guidance.

your vet's role

Your vet typically examines the eye, and general health, looking for a cause for the tearing. If the nasal opening to the duct is dry it indicates blockage of the duct.

Flushing of the duct can be helpful, but a predisposing cause for blockage should usually be sought. Staining of the cornea with fluorescein helps rule out ulcers.
Questions Your Vet Might Ask:
  • Can you see anything else going on with the eye(s)?
  • Are flies bothering the horse's eyes?
  • Is the skin around the eye pigmented or pink?
  • Does your horse seem normal otherwise?
  • Does the horse wear a fly mask?
  • Are one or both eyes affected?
  • What are the results of the Whole Horse Exam (WHE)?

Diagnoses Your Vet May Consider

The cause of the problem. These are conditions or ailments that are the cause of the observations you make.

Very Common
Less Common
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Treatments Your Vet May Recommend

A way to resolve the condition or diagnosis. Resolving the underlying cause or treating the signs of disease (symptomatic treatment)

Very Common
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further reading & resources

Author: Doug Thal DVM Dipl. ABVP