You walk out to the barn one morning and your horse's eyes are red and runny or swollen. Or, he is walking into the barn one day and he runs smack into the wall. Or, you go out into the pasture and find him under a tree, head down, eyes closed, totally withdrawn. Or, you may notice excessive shying or viciousness toward you or other horses.
Also known as Moon Blindness or Periodic Ophthalmia , Equine Recurrent Uveitis (ERU) is the most common cause of blindness in horses. Unlike many diseases, it does not have one single cause and, for this reason, has baffled researchers. Once started, it may cause blindness if its progression cannot be halted. Fortunately, while the causes cannot be foreseen or eradicated, its progression can in many cases be slowed or stopped by fast, aggressive and consistent care.
Signs include puffy, watering eyes, squinting, and red blood vessels at the sides of the eye and in the lids. Another major sign to look for is a pupil that is constricted when the horse is in the barn or in a darkened stall. A constricted pupil indicates that it is in spasm, and is very painful. Immediate treatment is needed to alleviate the spasm. Other signs may include head shaking, a runny nose, white spots or bleeding in the eye, matter or pus collecting, loss of balance, tripping, running into things or rubbing the eye. In some cases if you look across the surface of the eye you may even see ulcers. They look like little declivities, but usually you will need to stain the eye to see them and the untrained eye can still miss them. Additional signs that owners mentioned in a survey were: stops grazing, decreased appetite, swollen eyes, spookiness, blinking, avoidance of sunshine, and grumpiness. All of these could be signs ERU. Resist the urge to save money and time waiting for the vet by trying your friend's eye ointment from a prior eye problem. Call your vet immediately.
The difficult thing about this devastating disease is that many different things can cause it, and each horse's reaction to the disease and treatment is slightly different. Contrary to many people's understanding, ERU is not limited to Appaloosas. Over the last 10 years, the ERU Network has heard from just about all breeds and crosses. Appys and Quarter Horses have reported the most cases and Appys especially have a greater chance of losing sight once an eye is affected, but no horse, young or old, male or female is exempt from equine recurrent uveitis.
DEALING WITH YOUR HORSE ON A DAILY BASIS
Depending on the extent of the blindness, the horse may have blind spots, or a blind side. If he is blind or almost blind in one eye, he will lose his depth perception. He may trip on rises or dips in the path. At the onset of the disease, if you haven't already gotten him adjusted to it, start doing everything from both sides: leading, grooming, saddling, and mounting if you can.
Get in the habit of talking to him constantly so he knows where you are. Keep a hand on him while working around him so he can hear and feel where you are. When leading a horse that is blind in one eye, stay on the good side. Your first reaction might be that you will replace the horse's bad eye. The first time he jumps left because of something scary he sees with his good right eye, you will realize the importance of staying on the good side. Most horses will not willingly jump into you, but if they can't see where you are, in their fright you may get stepped on.
Traditional short-term treatment usually consists of using atropine to dilate the eye and reduce discomfort due to spasm of the iris. A steroid may also be indicated if the eye is not ulcerated or an antibiotic if the eye is ulcerated. In addition to the ointments and drops in the eye, bute, aspirin or banamine are fed to decrease the inflammation. In some cases, veterinarians will use the atropine for a few days and then stop it so that the pupil can start to constrict again. The idea is to keep the pupil moving so that synechiae, little pieces of protein that form strands in the eye, cannot cause the pupil to fuse in one position. If a fungus has gotten into the eye, additional treatment is needed as well as the above.
In addition to the standard treatments, owners are experimenting with alternative methods such as acupuncture, MSM, vitamins, yucca, apis mullica, bee pollen, clovite, chiropractic, herbs, hot and cold compresses and riboflavin.
Long-term management involves getting a handle on what triggers individual episodes. Unfortunately, that can be different at different times, but some of the big offenders are: wind, dust, getting chilled, stress of competition, a new pasture mate, losing a pasture mate, ammonia build up in the barn, injury, food, seasons changing, strong sun, severe cold, worming, bugs and flies, shots or going off the anti-inflammatory medicine. The best way to figure out the causes in your horse is to keep a daily log. In the log, note the wind and weather conditions, whether the horse was in or out, medications given, amount of exercise, temperament, and anything out of the ordinary. A booklet that has a month at a glance is great. Develop some abbreviations so it all fits. You will quickly be able to discern patterns and then possibly forestall future episodes. If it is windy or forecast to be windy, a hood with a clear bubble keeps the wind off the eye; wet and rainy, leave him in, etc. Many horses wear fly masks to cut down on the light and owners are also using dietary supplements to help build up the horse.
The goal is to keep the inflammation from starting. Allopathic long-term treatment will often consist of a daily or every other day dose of aspirin. It is considered to be the easiest NSAID (nonsteroidal anti-inflammatory drug) on the stomach, but can still lead to ulcers in some horses after a time. It involves experimenting and keeping detailed notes on the horse's progress. If you are using your horse to compete, the medications will have to be discontinued several days to a week prior to the competition.
The different aspects of the disease make it a challenge to diagnose and over the years have caused some horses to go undiagnosed for months or in some cases, years. Some veterinarians see a great many cases and are tuned in to watching for ERU. Others may never have come across a case and then it depends on whether they research it or have read about the disease or whether the owner of the horse can ask the right question: "What about ERU, equine recurrent uveitis?"
In summary, with equine recurrent uveitis, you have to evaluate and then handle each case individually. No two cases are exactly the same. It is very time-consuming and can be expensive if it continually reoccurs, but by being aggressive and diligent, you have a chance of saving your horse's vision and can save money in the long run if the disease is successfully halted or at least slowed down. One thing that cannot be stressed enough is that if you feel something is not right, the medications aren't helping, an episode is lasting too long, etc., trust your instincts and get a second opinion or consult a veterinary ophthalmologist. In the survey, of the horses in which the uveitis started in one eye and then spread, it spread to the second in 3-5 months in 41% of the horses. That means that you do not have months to experiment or to wait and see what will happen next.
(1) Marshall Scott, D.V.M., C.V.A., "Moon Blindness", Horse Illustrated, (December, 1993):14.
Mary Nelson got her introduction to equine recurrent uveitis through a horse she leased. The research and the ERU Network grew from there. She currently owns a Quarter Horse/Mustang gelding, 21, and a 10-year-old Arab mare she competes in competitive trail and endurance. She works full time in the accounting/finance department of an insurance company and she and her husband live in New Jersey.
THE ERU NETWORK
The ERU Network, with the assistance of many equine publications and the internet (one Network member placed our pamphlet on her website) has worked over the last 10 years to educate horse owners and vets about this disease. When I first started researching uveitis, there was almost nothing written for the horse owner, just articles published for veterinarians that could be found in vet school libraries. The ERU Network was started as a result of my frustration over not being able to learn anything about the disease or how to attempt to manage it.
Now that the word is out, people are talking and comparing notes, experimenting and learning how to better manage uveitis. Veterinarians are researching and working with implants and surgery. Practitioners and owners are experimenting with holistic and alternative therapies, and best of all, horse owners are asking their vets about uveitis and various treatment options.
Excerpt from ERU pamphlet: Ten years later, instead of the stock answer I received from my vet, "Get used to it, she's going to be blind", teams of vets and owners are getting aggressive to manage equine recurrent uveitis. One of the fastest growing additions in treatment options involves alternative therapies, herbs, acupuncture and chiropractic, to name a few. Since each case of uveitis reacts differently, owners going the 'natural' route need to either find a knowledgeable vet or practitioner or do a great deal of research on their own to see what works on their horse and to do it safely. Since uveitis is an immune-mediated disease, in simplified terms, "the blood is fighting the disease and the interior eye, while the eye is fighting he disease and trying to protect itself from being digested by the body's own blood," (1) some alternate approaches work at cleansing the horse's system while others replace or work in conjunction with traditional medicines to treat and reduce the number and severity of the flare-ups.
Some of the alternative therapies that members of the ERU Network have worked with are: Standard Process alternative therapy program - needs to be ordered through a vet or chiropractor; Go Max vitamin supplement; ABC's Plus, a nutritional supplement available from Advanced Biological Concepts; willow bark capsules as a substitute for aspirin or bute; Bach Flower Essences; Bioquench, an anti-oxidant product to boost the immune system that contains 77% grape seed extract as well as several other vitamins and also helps with skin problems from bug bites and itching; acupuncture; traditional Chinese medicines; Immune One, from Source One Naturals, glyconutritional supplement; Master Jack from Advanced Biological Concepts, designed to boost the immune system with a special emphasis on the eye; and Pro-bi also from Advanced Biological Concepts, a digestive aid good for horses under stress.