What is Uveitis in Horses?
Uveitis is an inflammatory disease of the equine eye. It can result in pain and permanent changes within the eye including corneal ulcers, glaucoma, cataracts and even blindness. Uveitis can be a one-time incident or it can become a chronic issue called Equine Recurrent Uveitis (ERU). It is a fairly common disease occurring in as many as 1 in 10 horses.
Symptoms of Uveitis in Horses
Signs of uveitis include:
Cloudiness of the cornea
Causes of Uveitis in Horses
The underlying cause of uveitis isn’t completely understood but Appaloosas are much more likely to develop it, so genetics may play a role. There are many environmental factors that can affect the onset and severity of uveitis as well.
The most common causes of uveitis include:
Infection (particularly leptospirosis)
How Veterinarians Diagnose Uveitis in Horses
Uveitis is primarily diagnosed through an ophthalmic (eye) examination by a veterinarian. The veterinarian will look at the structures in the back of the eye for signs of inflammation such as:
Larger blood vessels
Bullet-hole lesions in the retina
Changes to the optic disc
Particulates in the vitreous body (fluid within the back of the eye)
A tightly closed pupil and squinting are very strong signs of uveitis. If signs of uveitis keep recurring, your veterinarian may use a tonometer to check the pressure within the eye to see if your horse may be at risk for secondary glaucoma.
Treatment of Uveitis in Horses
The first step of treating uveitis is identifying the cause. If a traumatic incident caused the inflammation, pain and inflammation management may be all that is required. If leptospirosis is suspected, antibiotics such as doxycycline may be needed. Autoimmune cases will require regulation of the immune system using topical medications such as cyclosporine or steroids.
All cases of uveitis require inflammation and pain management. Medications including phenylbutazone and banamine may be recommended by your veterinarian and can be given orally (by mouth).
Eyedrops or ointments can be helpful for pain and inflammation; some options include dexamethasone or cortisone-containing ointments, and diclofenac, which is a non-steroidal anti-inflammatory medication.
In chronic cases of uveitis that respond poorly to typical treatment plans, referral to an ophthalmologist may be necessary. Additional treatments by the ophthalmologist may include cyclosporine implants or gentamicin intraocular injections.
In very severe cases where the pain and inflammation cannot be controlled, enucleation (removal of the eye) may be the best option for the horse, especially if the eye is no longer visual.
Recovery and Management of Uveitis in Horses
Ultraviolet (UV) light is known to worsen uveitis cases, so a UV-protective fly mask can be extremely helpful for long-term management, especially in cases of ERU.
Uveitis can predispose a horse to corneal ulcers, glaucoma, and even blindness. This means that being diligent in preventing and managing flare-ups is important for the long-term comfort of the horse.
Uveitis in Horses FAQs
Can uveitis in horses be cured?
Traumatic uveitis or cases secondary to leptospirosis infections can be cured. However, cases with autoimmune causes can be managed but are likely lifelong issues.
Is uveitis in horses contagious?
No, uveitis is not contagious.
Can uveitis clear up on its own?
In rare cases, traumatic uveitis can clear up on its own. Because the consequences of uncontrolled uveitis are so severe (glaucoma, blindness) it is important to have any horse that is squinting or showing symptoms of pain evaluated right away and to be diligent in treatment and management.
- Wahlert, Sarah. Equine Recurrent Uveitis (ERU). Equine Recurrent Uveitis (ERU), UMN Extension.
- Young, Amy. Equine Recurrent Uveitis. UC Davis School of Veterinary Medicine, Center of Equine Health. 2022.
Featured Image: iStock.com/Alexia Khruscheva
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