What are Conjunctivitis?
The very thin membrane that covers the inner eyelid over to the cornea is known as the conjunctiva. The conjunctiva is quite important to the horse, as it is responsible for tear production, healing an injured cornea, and protecting the eye from foreign objects. Keeping the conjunctiva healthy and productive is crucial because ignoring a conjunctiva with problems can cause harm, and possible blindness, to the horse.
Conjunctivitis is also referred to as pink eye. This is because a horse with conjunctivitis is characterized by one or both eyes becoming reddened, or pinkish. It is also characterized by drainage, swollen eyes, encrusted eyelids, and general discomfort.
Horses with conjunctivitis can have underlying viral or bacterial infections that have caused the condition. Irritants from the environment can also cause the horse’s eyes to become irritated, anywhere from mild to severe. It is always important to observe your horse’s eyes to be sure they look healthy and clear.
Conjunctivitis in horses occurs when the eye becomes inflamed and infected, thus causing painful discomfort and discharge.
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Symptoms of Conjunctivitis in Horses
The most common symptom of conjunctivitis is red or pink eyes. Other symptoms include:
- Shaking of the head, as if in distress
- Crusted-over eyes, unable to open
- Pain in the eyes
Conjunctivitis comes in two types: bacterial and viral. There are other eye conditions that may affect horses. Other eye conditions include:
- Equine corneal ulcers
- Optic nerve disease
- Diseases of the retina
- Diseases of the visual cortex
Causes of Conjunctivitis in Horses
Conjunctivitis is caused by either a viral infection or bacterial infection. Specific causes include:
- Dust particles
- Upper respiratory tract infections
- Discharge from the nose and sinuses
- Systemic viral illnesses
- A scratched cornea that becomes infected
Diagnosis of Conjunctivitis in Horses
If your horse is exhibiting eyes that are pink or red, make an appointment with your veterinarian. Once you take your horse to the equine veterinarian, he will need to perform a variety of tests to be sure your horse indeed has conjunctivitis.
The visit will begin with the veterinarian reviewing the history of the horse and asking questions pertaining to when the symptoms began and the severity of the symptoms. He will ask questions about your horse’s living conditions, such as if he lives in an area where there is a lot of allergens and dust. He will then take a careful look at the affected eye and note any symptoms and when he observes. He may perform blood work or other laboratory testing to check for any underlying infections or conditions which may contribute to the horse’s eye disorder.
The veterinarian will be able to make a specific diagnosis with laboratory testing on samples of the conjunctiva, known as conjunctiva scrapings. He may also perform a Schirmer tear test, which is a test that measures tear production. A thin piece of film is placed on the eye and measures tear production using colored dye. Since the conjunctiva is so valuable in tear production, this is an important measure of specifically what is happening within the eye.
The veterinarian may perform a biopsy of any conjunctiva or tissue around the eye as well. Once your veterinarian has made the diagnosis of conjunctivitis, treatment will begin.
Treatment of Conjunctivitis in Horses
Treatment depends on if the conjunctivitis is bacterial or viral, and the severity of the condition. There are several different reasons that the horse may develop conjunctivitis. Treatment methods may include:
If your horse has a pus discharge, a topical antibiotic will be prescribed. This will be put in the infected eye of the horse. Typically, antibiotics begin to work quickly.
Other methods of treatment will be used, but this depends on the injury. For example, if the eye has an object lodged within it, the veterinarian will treat the eye by removing the object, and then possibly following up with an antibiotic.
If your horse has conjunctivitis due to allergies, your veterinarian will prescribe either allergy medications or eye drops that treat eye allergies and protect the eyes.
Recovery of Conjunctivitis in Horses
Conjunctivitis is very treatable with specific antibiotics and supportive care. Once you have the proper treatment for your horse, the veterinarian will give you detailed instructions in giving the medications. The medication or medications are usually in the form of antibiotic eye drops or gel if the horse has a bacterial infection.
It will be important to administer the medications at the same time every day. If a dose is missed, ask your veterinarian what you need to do. With the medication, you will begin to see rapid improvement in the eyes.
It may be difficult to prevent conjunctivitis, as the horse will be exposed to specific environmental agents as he is outside or even in his stall. However, frequent eye-checks can help you catch any abnormality early enough to where infection may not occur.