Corneal Ulceration in Horses

Corneal ulcers -- injuries to the transparent outer coating of the eye -- are usually the outcome of some type of trauma to the eye. It may have come about as the result of running into something, violent contact with another horse, a foreign object entering the eye, fungus or bacteria in the surrounding environment, and harsh dust entering the eyes. All of these can be considered traumatic incidents. A less severe type of injury to the cornea, an abrasion, may heal itself, but it can also be deeper than it appears on the surface, or it may become infected and turn into a more severe ulcerated injury.

Once the eye has an abrasion, or ulcer, it can easily become infected, and these infections have the potential to turn a corneal ulcer into a serious health issue, sometimes breaking down the corneal tissue and leading to a defect of the eye that needs more invasive treatment than if it had been given immediate treatment. 

Symptoms and Types

• Redness in the eye
• Severe pain
• Swelling in the eye
• Tears running down the face
• Closed or nearly closed eyelids
• Eye infection(s)
• Inflamed lining of the eye (conjunctivitis)
• Dull corneal surface (i.e., cloud in appearance)
• Blood vessel development through the cornea

Causes

Corneal ulcers are often due to eye trauma, whereby foreign objects come into contact with the eye. Other secondary issues include bacterial, viral and fungal infections.

Diagnosis

Your veterinarian will perform a thorough physical and ophthalmological exam on your horse, taking into account the background history of symptoms and possible incidents that might have led to this condition. A fluorescein stain, a non-invasive dye that shows details of the eye under blue light, will be used to examine the eye for abrasions or foreign objects.

Often, an abrasion or infection is easily diagnosed by a veterinarian simply by peering into the eye. An ulcer should be visible to the medically trained eye, as well as the side effects to the condition itself. If it appears that an infection is present, your veterinarian will need to take samples from the cornea by scraping away some of the tissue for laboratory testing. Any discharge or fluid will also be collected for testing. A specific diagnosis is essential, as not all drugs are appropriate for treating an injured eye, and some may in fact do more harm.