Equine Uveitis

Uveitis is an inflammatory condition of the uveal tract of the eye (iris, ciliary body and choroid). It can be caused from trauma, corneal ulcers, tumors and lens luxation. Most people are aware of the immune-mediated form of equine recurrent uveitis (ERU) or moon blindness. This is one of the most common causes of blindness in the horse. 
                Clinical signs are excessive tearing, holding the eye partially or completely closed and redness of the membranes. These horses are often very sensitive to light. The veterinarian will examine the eye with an ophthalmoscope and see varying degrees of constriction (miosis) of the pupil and aqueous flare (protein in the anterior chamber) Often there will be adhesions to the internal structures and a haziness or blue color to the surface (cornea). Cataracts are often a sequelae to the disease. Uveitis is very painful and requires veterinary attention and proper medication administered by the owner frequently.
                Classic uveitis is very noticeable and causes pain & inflammation that lasts about 2 weeks. With ERU the eye can become quiet for an indefinite period of time, but eventually flares up and becomes active again. This process can occur indefinitely. The subclinical form doesn’t typically show signs of pain but the inflammatory process continues to damage the internal structures after the active process. Unfortunately, the horse eventually can become blind without the owner noticing the ongoing symptoms.Appaloosas are one of the most commonly affected by ERU, however it can affect any breed.
Posterior uveitis is uncommon but affects the structures behind the lens. This can lead to detachment of the retina. Uveitis is caused by a number of things including injury, infections (such as Leptospirosis) and an immune reaction to environmental factors. To date, there is no cure for ERU but proper medical management can help slow the process. Treatment includes topical & systemic non-steroidal anti-inflammatory drugs (NSAID’s) & Steroids. Also, medication such as atropine to dilate the pupil will help prevent adhesions and allow better function.
                If medical treatment doesn’t work, surgical options at a university are available. These include a vitrectomy and an implantation of a sustained release cyclosporine device. These have shown tremendous promise for ERU cases. They generally last for four years and significantly decrease the number of active episodes.

No Comments Yet.

Leave a comment