Common Eye Problems in Horses

Your horse’s vision is the primary way they take in their surroundings and navigate their environment. Loss of eyesight is one of the most common reasons for the premature end of a horse’s riding, working, or competitive career.
Squinting, watery eyes, swelling, redness, discoloration to any part of the eye, and sensitivity to sunlight are all signs that your horse needs to be seen by your equine veterinarian. Eye issues should always be taken seriously as even a seemingly simple infection or superficial injury can lead to complications and loss of vision. Watch out for symptoms of these five common eye problems in horses.

Eyelid Laceration The placement of your horse’s eyes on each side of their head makes them particularly vulnerable to eyelid lacerations. As they scratch an itch or brush up against rough or sharp surfaces, they can tear their eyelid, leaving their eye vulnerable to infection. What’s more, what may look like a small superficial eyelid injury may also affect the cornea. Eyelid tears should be considered an emergency and may require stitches. With treatment, they typically heal without further complication.

Corneal Ulcer The cornea is the transparent outer layer of your horse’s eye that allows them to see clearly. A corneal ulcer is a painful scratch or abrasion on the cornea. A superficial scratch may clear up on its own in a week or two. However, in some cases the scratch can develop a bacterial or fungal infection, or it may worsen if your horse rubs their eye.
If your horse has a corneal ulcer, they may become extra sensitive to light. They may squint and the pupil of the affected eye may appear small. The eye may water and your horse might show signs of pain, and may attempt to rub at their eye.
Call your veterinarian immediately upon noticing any eye-related symptoms. Do not use any over-the-counter treatments or drops unless under the guidance of your vet. Your veterinarian can dye the cornea to determine the severity of the ulcer and prescribe a treatment to prevent infection and speed up healing.

Moon Blindness Equine recurrent uveitis, or moon blindness, is the most common cause of vision loss in horses. During an episode, the middle layer of the eye becomes inflamed, causing tearing, pain, redness, and swelling. An episode may last a few days, but in some horses, recurring episodes lead to glaucoma or cataracts, and eventually blindness.
The initial onset is often mistaken for irritation or mild injury to the cornea. Your veterinarian can confirm the diagnosis and may prescribe steroids or other treatments to help reduce inflammation and vision loss.

Cataracts Cataracts are cloudy or hazy areas in the eye caused by the breakdown of proteins in the lens. Though not painful, cataracts impair your horse’s vision and may eventually cause blindness. Cataracts in foals are typically caused by a congenital defect. In older horses, they’re typically caused by equine recurrent uveitis.

Glaucoma Glaucoma describes damage to the optic nerve associated with abnormally high pressure in the eye. The initial symptoms are usually subtle and tend to go unnoticed. At first, there may be slight redness, enlargement of the eyeball, and dilated pupils. As the disease progresses, swelling and redness become more noticeable, and discoloration of the cornea is also common. Caught early, optic pressure can be managed to slow the progression and prevent vision loss.

As eye problems in horses can have very similar symptoms, it’s important to see your veterinarian for a diagnosis before attempting treatment.