Equine Recurrent Uveitis Case Study

Immune-mediated disease is essentially the breakdown of the immune system. An example of this disease is Equine recurrent uveitis (ERU), also known as moon blindness, affects horses. It is not contagious and symptoms of this disease are swelling of the eyelids, corneal edema, and blindness. There is no cure for this disease yet and the cause of it has yet to be discovered. Horses with acute uveitis and heavy lymphocyte influxation have a greater chance of developing ERU. When the condition is chronic, it can cause blindness, glaucoma, lens luxation, cataracts and retinal degeneration. Parasitic, bacterial, viral, and trauma can cause ERU as well. Leptospira ssp has also been known to cause ERU.

The symptoms observed by owners are often subtle and can range from very mild tearing or swelling of the eyelids, to more obvious squinting and noticeable change in appearance (cloudiness) of the eye. One or both eyes can be affected, and though any horse can be diagnosed with ERU, at risk breeds include Appaloosas, European warm bloods, and draft breeds.
A definitive diagnosis of ERU is typically only made after the horse has had several recurrent episodes of uveitis in one or both eyes. A thorough ophthalmic exam of anterior and posterior eye is done. Fluorescein eye test is also used to see if it is ulceration keratitis or uveitis. The long-term prognosis for the eye in horses diagnosed with ERU is guarded. Some horses respond favorably to treatment, while others develop secondary problems related to the inflammation inside the eye. Early recognition and treatment intervention are important in an effort to maximize the amount of time a horse retains vision and comfort of the affected