Eye problems in the horse were discussed by Dennis Brooks, DVM, PhD, Dipl. ACVO, a professor of ophthalmology at the University of Florida, at Horseman's Day during AAEP.

"There are really only two ophthalmic disease: Corneal ulcers and everything else," said Brooks. Therapies are different, and some therapies for the "everything else" can make ulcers worse, cautioned Brooks.

He has been seeing more corneal stromal abscesses--or small spots of infection--in horse corneas. These horses are painful and fluorescein stain doesn't work (to show the defect). There is a small puncture in the cornea with introduction of microbes or a foreign body. Epithelial cells migrate over the hole or defect and form an abscess.

"It is often misdiagnosed," he said. "Many cases are fungal, so they are medically non-responsive. These horses need corneal transplants."

One of the most common causes of blindness in U.S. horses is recurrent or persistent uveitis, also known as moon blindness. This is an autoimmune system disease, and it is worse in the Appaloosa (with some statistics showing a 20% occurrence in both eyes in the Appaloosa population). This is a very painful disease that was first described in 300 A.D.

Brooks said all parts of the eye are damaged, and that not all moon blindness cases look the same or have the same signs. Medical therapy works in short term, he says, but this disease doesn't go away. He said in Appaloosa and Paint horses, the problem can be quite prolonged.

In cases where the horse can still see, Brooks will make an incision in the white part of eye and put in a plastic implant that continually releases cyclosporine (an immunosuppressant drug). This procedure was developed at North Carolina State University. Brooks said some horses respond to acupuncture for moon blindness.

Brooks' closing remarks were to remember that sight is valuable. Protect it in your horses! (See article #4975 online.)

About the Author

Kimberly S. Brown

Kimberly S. Brown was the Publisher/Editor of The Horse: Your Guide To Equine Health Care from June 2008 to March 2010, and she served in various positions at Blood-Horse Publications since 1980.

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