Symptoms of glaucoma include red, cloudy, and/or painful eyes. The redness usually occurs on the sclera (white part of the eye) and the conjunctiva (the mucous membrane covering the sclera). Cloudiness occurs in the cornea and inner part of the eye. Pain usually manifests as squinting and tearing.
The only sure test of whether a horse is suffering from glaucoma is to measure his intraocular pressure (the pressure within his eyeball) with a tonometer; in the case of glaucoma, the pressure will be unusually high. But not all veterinarians have a tonometer–and without it, glaucoma is easy to mistake for equine recurrent uveitis, which is much more common in horses and the leading cause of equine blindness; the symptoms of the two are very similar. Yet because treatments for the two conditions are different-and because glaucoma is harder to treat-an incorrect diagnosis can be very dangerous.
Glaucoma in horses tends to be chronic, but it can be cured if treated early enough. Treatments are similar to those for people: oral and topical medications, and even laser surgery. (Laser surgery for equine glaucoma has been around for more than five years; it costs about $600, depending on the area of the country. Success is related to the individual case and the clinical signs associated with it.)
If your horse’s seeing eye shows any of the above symptoms, have your veterinarian examine it. Both equine recurrent uveitis and glaucoma (primary or secondary) can lead to blindness, so proper diagnosis and treatment is crucial.
Not all veterinarians are comfortable diagnosing eye conditions. If, together, you and your vet have any doubts about his performing a diagnosis, consult a specialist. Your local veterinary school probably has at least one ophthalmologist on staff. Another way to find board-certified ophthalmologists in your area is to go to the American College of Veterinary Ophthalmologists’ Web site at www.acvo.com.
Is His Eye Infected?
Q. I sometimes find my horse’s eye discharging mucus. When I wipe the corner of his eye, I can see mucus filming his eyeball. He likes to shove his face into his pile of hay, so I wonder whether debris is irritating his eye or he’s picked up an infection-and what I should do about it.
A. Some daily discharge from horses’ eyes is not unusual. But if you need to wipe your horse’s eye more than once a day, have your veterinarian examine him. Debris and other matter may be getting into his eye from his hay. Or he may be suffering from something more serious, such as an ulcer (abrasion) or conjunctivitis (infection). Without treatment, these problems can become further infected and may possibly even result in blindness.
If he’s suffering from an ulcer, you’re most likely to notice the discharge in only one eye, and the discharge is probably clear and watery. If he has conjunctivitis, both eyes are likely to be affected, and the discharge is usually thicker and more mucus-like (although none of these characteristics is exclusive to one condition). Whatever the specifics, they warrant a check by your veterinarian.
Symptoms of conjunctivitis in a horse are like those in any animal: The conjunctiva (the mucous membrane around the eyeball) is red and/or puffy, and it usually itches. Your horse may try rubbing his face to relieve the itching, and/or he may squint or tear in obvious discomfort.
Both eye ulcers and conjunctivitis may be treated with antibiotics. Conjunctivitis is also often treated with anti-inflammatories such as corticosteroids. But corticosteroids make ulcers worse–so it’s very important that an ulcer be ruled out before treatment decisions are made.
If you’re concerned that your horse’s eye looks infected and is not improving with treatment–or if your veterinarian is not comfortable diagnosing and treating eyes–ask him or her about consulting a specialist. See the information I gave with the glaucoma question above for how to find board-certified ophthalmologists.