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Last updated on
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Key takeaways

Eye redness is a common symptom in horses that is associated with ocular conditions.

  • Redness may affect the tissues around the eye, the white part of the eye (sclera), or occur within the eye itself
  • Causes include injury or irritation, cancers, infections, and immune-mediated diseases
  • Some conditions associated with red eye(s) can impact vision, and affected animals benefit from emergency veterinary intervention to begin treatment
  • Diagnostics for red eyes include an ophthalmic exam, cytology, and biopsy
  • Treatment depends on the underlying cause, although antibiotics, anti-inflammatories, and pain control medications are common
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A closer look: Red Eye in Horses

Eye redness is a common symptom in horses, and is often associated with serious conditions, such as corneal ulcers or uveitis, that may negatively impact a horse’s vision. Horses presenting with eye redness benefit from emergency medical attention for the best chance at preserving vision.

Possible causes

Risk factors

Eye redness can take different forms.

Redness often presents as swelling and irritation of pink tissue around the eye. This form of eye redness is associated with conditions such as conjunctivitis, traumatic injury to the eye, or irritation such as from foreign bodies around the eye.

The white part of a horse’s eye (the sclera) may redden as part of similar disease processes. Other more serious causes of scleral reddening include endotoxemia or other gastrointestinal infections allowing bacteria to proliferate in the bloodstream.

Hyphema refers to blood within the front chamber of the eye, developing as a result of blood clotting or an injury.

Testing and diagnosis

Diagnostics include:

  • Physical examination
  • Ophthalmic examination
  • Tear production testing
  • Fluorescein staining
  • Intraocular Pressure (IOP) tests
  • Cytology
  • Biopsy

Treatment varies depending on the underlying condition. Antibiotics, anti-inflammatory medications and pain control are common. With severe conditions, the eye may need to be surgically removed.

Similar symptoms

Eye redness is self evident and not likely to be confused with other symptoms.

Associated symptoms


No Author - Writing for Horse Side Vet Guide
No Author - Writing for Horse Side Vet Guide
Tammy Miller Michau, DVM, MS, DACVO - Writing for Horse & Pony
No Author - Writing for Horse Side Vet Guide
No Author - Writing for Working Equid Veterinary Manual

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