What to do if your horse has an eye infection

Disclaimer: This article, its content, and its related references do not constitute veterinary advice and should not be considered a substitute for veterinary care. If your pet is showing any symptoms that could indicate a medical emergency, please seek immediate emergency care.

Horses have sensitive eyes that can easily become injured and infected. Viral, parasitic, fungal, and bacterial infections in the eye are common in horses. It’s important for horse owners to be able to recognize the signs of an eye infection and know when to seek veterinary attention. If you have a horse, read on to learn:

• Common symptoms of horse eye infections
• Causes of eye infections in horses
• How eye infections in horses are diagnosed and treated

While there are many ways a horse’s eyes can develop an infection, secondary injuries from foreign objects or insects are common causes. Environmental debris or trauma can cause abrasions or scratches on the eye surface (corneal ulcers), which allow bacteria and other infectious agents access to the eye. In addition, upper respiratory viral infections, infections near the eye, eye and nasal disorders, and immune-mediated diseases can also contribute to a horse developing an eye infection.

Symptoms may include abnormal eye discharge, red or bloodshot whites of the eyes, swollen or red tissue around the eyes, and signs of eye discomfort. Treatment for ocular infections varies based on the type, severity, location, and underlying cause of the infection.

Prompt veterinary attention is warranted when a horse has signs of an eye infection. Untreated eye infections can quickly become worse and lead to permanent eye damage.

Eye infections develop when an infectious agent enters and affects the eye or the tissues surrounding the eye. Infections can be caused by bacterial, viral, parasitic, or fungal pathogens. Multiple parts of the eye can become infected:

• Eyelid (blepharitis)
• Conjunctiva (conjunctivitis)
• Cornea (keratitis)
• Interior structures (uveitis)

Uveitis and secondary infections from eye injuries are two of the most common types of ocular infections in horses.

Eye infections in horses can have varying symptoms depending on what part of the eye is infected and the underlying cause of the infection. Common signs of equine eye infections include:

• Excessive tearing
• Eye discharge
• Excessive blinking or squinting
• Rubbing the eyes
• Reddened or bloodshot eyes
• Red or swollen tissue around the eyes
• Sensitivity to light
• Cloudy eyes
• Signs of vision loss or impairment

Eye discharge can vary in amount, color, and consistency. “Cloudy eyes” can refer to a hazy appearance on the surface of the eye or within the eye itself, depending on what part of the eye is affected. A horse may have an infection in one or both eyes. An untreated eye infection may continue to get worse and additional symptoms can develop.

Depending on the underlying cause of the eye infection, a horse may have other symptoms, including:

• Nasal discharge
• Coughing or sneezing
• Loss of appetite
• Lethargy

“Eye infections can be a primary condition where there is direct contact of the pathogen with the eye, or they can occur secondary to another ocular condition or even systemic disease,” explains Dr. Jamie Lecky. “Secondary infections from systemic disease are likely to have additional signs of illness.”

Is an eye infection an emergency in horses?

Horses have very sensitive eyes, so prompt veterinary care is recommended any time they exhibit signs of an eye condition. The underlying condition may or may not be an emergency, but it’s impossible to know until it’s accurately diagnosed by a vet. Diagnostic testing also rules out infectious diseases that can spread to other horses, so it’s best to get medical attention right away.

Horses commonly get infections after an eye injury, which often occur due to:

• Bacteria-carrying flies or other insects biting around the eye
• Foreign material, such as dirt, pollen, hay, and grass, entering the eye

Bacteria and other infectious agents can easily enter an injured eye. In addition, horses often rub an irritated eye, allowing the injury to become contaminated.

Other reasons horses develop eye infections include:

• Contagious diseases, such as equine herpesvirus
• Immune-mediated eye conditions
• Congenital deformities
• Infections around the eye

Diagnosing ocular infections in horses involves:

• Identifying which part of the eye is affected
• Identifying the infectious agent
• Identifying the underlying cause of the infection

Veterinarians may diagnose a horse’s eye infection and rule in or out other medical conditions by using:

• Thorough physical and eye exam
• Fluorescent eye stain to check for corneal ulcers or scratches
• Schirmer tear test to measure tear production
• Intraocular pressure test
• Assessment of ocular reflexes
• Testing for infectious disease
• Bacterial culture
• Environmental analysis

In cases where the infection is potentially secondary to another health issue, other non-ocular diagnostic tests may be recommended. A definitive diagnosis is necessary to create an effective treatment plan. Do not attempt to treat or medicate your horse’s eye issue without consulting a veterinarian; ineffective treatment delays proper care, allowing the infection to get worse, and can also make eye damage worse.

Treatment options for equine eye infections vary depending on the type, location, and underlying cause of the infection. A treatment plan may involve:

• Eye drops or ointments with antibiotics, antifungals, or anti-inflammatories
• Changes to housing or environment (such as improved ventilation, avoiding use of dusty bedding or hay)
• Use of a fly mask
• Pain medication
• Antiparasitic medication
• Minor procedures or surgery

In advanced or complicated cases, referral to an equine eye specialist may be recommended. Always follow a vet’s instructions involving eye care and treatment — a horse’s eyes are highly sensitive, and improper treatment may worsen the damage.

Promptly talk to a veterinarian any time you notice changes in your horse’s eye health. Untreated eye infections and other eye conditions can rapidly get worse and lead to permanent damage or blindness. Ocular symptoms can also indicate an underlying infectious disease that can affect other horses. You can talk to an online vet for guidance on how best to proceed for your horse’s specific condition.

How do you treat a horse’s eye infection?

Equine eye infections may be treated with topical medication, oral medication, environmental adjustments, use of a fly mask, and various procedures or surgeries for the eye. Treatment options vary depending on the type of infection, what part of the eye is infected, and what is causing the infection.

What are the most common causes of eye infections in horses?

Secondary infections caused by eye injuries, insects around the eyes, or foreign bodies are some of the most common reasons for eye infections in horses. It’s important to regularly check on your horse’s eye health and alert a veterinarian if any symptoms are seen.

How do you treat eye discharge in horses?

Ocular discharge can point to an eye infection, upper respiratory infection, or other ocular or non-ocular condition. Due to the wide variety of conditions that can have similar symptoms, an accurate diagnosis is necessary to determine the underlying cause of the discharge. In many cases eye discharge may be treated with oral or topical antibiotics, antifungals, anti-inflammatories, or pain medication. Other treatment methods may be necessary depending on the cause.