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


Swelling around One Eye or Eyelid


Swelling around only one eye or involving only one eyelid is often the result of a traumatic injury. It can also be caused by a foreign body or an insect sting. Infection of the tissues around the eye can also cause severe swelling. Horses that have a corneal ulcer or other inflammatory eye disease also show swelling around the affected eye.

  • Code Red

    Call Your Vet Immediately, Even Outside Business Hours
    • If you notice other problems with the eye or the eye seems inflamed and painful.
    • If you feel the problem is severe or has come on suddenly.
  • Code Orange

    Call Your Vet at Their First Available Office Hours
    • If the signs are very mild and the eye appears normal otherwise.

your role


What To Do

Assess your horse's eye and eyelid looking for evidence of injury, a foreign body or any other abnormality and report your findings to your vet. Always assess the other eye for similar signs. Do your best to ensure that there is only swelling around one eye.

Given the importance of your horse's sight, do not allow this condition to continue or worsen over time. Because of the possibility of injury to the eye itself, your vet should examine the horse.

You may flush the horse's eye with saline, if it is easy to do so. If you have an eye ointment or drops, talk to your vet about whether or not you may apply it until they examine the horse. Apply a fly mask and keep your horse quiet until your vet can see it.

your vet's role

Your vet will seek to determine whether the eye itself is injured and if so, whether special treatment is needed. They may stain the eye with fluorescein to rule out corneal ulcer. Once they have assessed the eye and determined the general nature of the injury, they may treat the swelling symptomatically.
Questions Your Vet Might Ask:
  • Can you see the appearance of the eye itself?
  • If you can see it, do you see any injury, foreign body or abnormality?
  • Does the horse appear to be itching the eye?
  • Have there been large numbers of flies?
  • Does your horse wear a fly mask?
  • How is your horse's attitude and appetite?

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
more diagnoses

Author: Doug Thal DVM Dipl. ABVP