CEPS/Veterinary Extension
2938 Vet. Med. Basic Sciences Bldg.
2001 S. Lincoln Ave.
Urbana, Illinois 61802
Phone: 217/333-2907

By Kimberly Meenen
Information Specialist
University of Illinois
College of Veterinary Medicine

An irregularity in your horse's eye or eyelid may not seem like a big deal, but some ocular diseases can very quickly progress to blindness and even loss of the eye itself. According to Dr. Paul Gerding, an ophthalmologist at the University of Illinois College of Veterinary Medicine at Urbana, any abnormality of the eye should be examined by a veterinarian immediately.

"Above all," stresses Dr. Gerding, "do not attempt to treat the disorder yourself." While different eye diseases may produce similar signs, using medications that you may have around the barn for a previous problem can make a potentially salvageable condition much worse.

Providing no medical attention can be just as bad, since only two to three days are required for some eye lesions to produce permanent damage. A veterinarian should examine the eye as soon as you see something wrong with it.

Your horse needs to be examined by a veterinarian if it has an obvious lack of vision, or if you suspect its vision may be impaired due to an increased "spookiness" in the animal to ordinary objects. Excess tearing (where the side of the face is wet), holding eyelids closed, aversion to sunlight, redness of the white part of the eye, a small pupil, or a white, hazy cornea (corneal edema) are all signs of an eye disorder. Owners should not hesitate to contact their veterinarian when their horse is displaying one or more of these signs.

"Horse corneas scar easily, and can look like corneal edema, one of the signs of an eye disorder," explains Dr. Gerding. "A scar is not a problem, but it is a good idea to bring the horse in anyway just to make sure it does not have something more serious."

One of the most common acquired eye conditions in the horse is "moon blindness" or equine recurrent uveitis. The medical term refers to the fact that it is an inflammation of the eye that comes and goes. Signs of moon blindness may be invisible the first few times the horse has the inflammation, but each time it occurs, a little more damage to the eye is done. By the time signs are evident, it may already be too late to do anything about it, and cataracts commonly result. The disease can be present in one or both eyes, and has many causes. Treatment may involve oral medication for the rest of the animal's life to decrease the number and severity of the attacks.

Corneal ulcers are another common eye injury horse owners are likely to encounter. These are scratches or abrasions of the corneal surface that may be serious by themselves, but can become even more critical if they become infected. While corneal bacterial infections are more likely to develop quickly, fungal infections tend to develop slowly. Both can be very serious problems that can cause permanent blindness. In severe cases, surgery may be necessary. Even without surgery, medical treatment is aggressive, requiring horses to stay in the clinic two to four weeks with hourly dosing for the first three to five days.

The third eye disorder that horses are likely to acquire is an injury or laceration to the eyelid. The eyeball may have been involved as well, so a careful examination of the lid and globe is important.

"It is critical that veterinarians see these kinds of injuries immediately since success depends on quick treatment," says Dr. Gerding.