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Equine Health Resource

Eye has Ulcer or Scratch on Surface

Code Red - Call Your Vet Immediately, Even Outside Business Hours

Code Red - Call Your Vet Immediately, Even Outside Business Hours

  • Most eye problems are considered veterinary emergencies.

You notice that there is an erosion of the smooth, glassy surface of the clear part of the eye (the cornea). In most cases, these wounds to the surface are very hard to see without staining of the eye with a special dye.

Erosions and ulcers on the surface of a horse’s eye are common. In fact, corneal ulcers and abrasions should always be suspected whenever there is any eye injury. Ulcers can worsen fast and threaten the entire eye.

Contact your vet immediately with any eye injury because delay in diagnosis or treatment can have sight-threatening consequences.


Assess the eye, taking note of other expected signs including squinting, swelling, drooping lid, tearing, reddening and grayness of the cornea.


Your vet will assess the overall health of the horse and health of the eye, and then determine the severity of the ulcer, often using fluorescein dye. Fluorescein is a bright green dye which adheres to areas of the cornea (clear front part of the eye) in which the surface layer has been lost. In this way, it illuminates and maps the extent of the damage, which can be hard to see without it.

Helpful Terms & Topics in HSVGWritten, Reviewed or Shared by Experts in Equine Health

Author: Doug Thal DVM Dipl. ABVP


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