Equine Recurrent Uveitis

These are pictures of Girl's most affected eye, her better eye looks almost normal except for maybe a little clouding.
This eye has also shriveled somewhat due to the advancement of the disease.


Little Girl has Equine Recurrent Uveitis,
sometimes known as Moon Blindness.

Girl at about 6 years old,
about the time when she first started having eye problems.

Onset of Disease

Little Girl is 26 years old and I have had her since she was 5 months old. Her eye trouble started when she was about 6 years old. She had an injury to her eye and either the injury started the disease or the condition caused her to injure her eye. She had surgery to repair her injury and has had recurrent episodes. She is blind in 1 eye and can see movement with the other. She also suffered a detached retina probably when she reared up in her stall and hit her head on a beam. She also has cataracts. Even though she is partially blind she still can run and buck as much as the rest as long as her ringbone is not bothering her to much. She must be spoken to as you approach her so as not to frighten her but otherwise she does quite well. No one pushes her
around in the pasture.

Girl at 26 years old.


Treatment of equine uveitis consists of topical atropine, to both dilate the eye and reduce discomfort, and topical antibiotics. A steroid may also be indicated, but should only be used if the eye is not ulcerated. Steroids in an ulcerated eye can worsen the condition. In addition to topical treatments, I also use Bute to decrease inflammation and pain. During a flare up she has to stay inside in a dark stall and is turnout at night. Since we moved to our own place over 10 years ago she has only had one slight flare up but she still wears the fly-mask year round. During the winter, if there is a bright glare from the snow, a fly mask helps to shield the eye from the brightness. It also cuts down on the amount of wind directly hitting the eye.

Signs of an Eye is in Distress

It is a disease of the horse's eye that can be caused by many different things -- bacteria, virus, parasites, or trauma. Signs that an eye is in distress include redness, swelling, pus, pupil constriction in the dark, cloudiness, squinting, and photophobia. Uveitis is often diagnosed as something far less serious and valuable treatment time is lost. If not treated aggressively from the onset, there is less chance of saving sight in one or both eyes. Unfortunately, even with very aggressive treatment, some eyes cannot be saved, but in other cases the disease can be slowed down. When the uveitis first starts, if the original cause can be determined then additional treatment may be used depending on the cause. The usual short term treatment includes atropine to dilate the eye, followed by either a steroid or antibiotic. Treatment must be prescribed by a veterinarian because if a steroid is used when the eye is ulcerated, dire consequences can result. Bute, banamine or aspirin are used as anti-inflammatory agents along with the other medications. After the original episode has been successfully treated, the inflammation and signs will disappear and the eye may appear to be normal or almost normal. At sometime in the future, if it is recurrent uveitis, a set of circumstances will cause the eye to have another episode. The circumstances can be internal; external such as wind, dust, pollen; stress of any kind; or due to stopping the anti-inflammatory medicine prematurely. With recurrent uveitis, the episodes continue to occur. Each one lasts a little longer and each time the eye loses a little more sight.


Atropine works by paralyzing some of the muscles of the iris, thus stopping the painful spasm and allowing the pupil to dilate. The dilation of the pupil is very important because if it stays constricted and in contact with much of the lens in the presence of inflammation, the chances are greater for the iris to become scarred and attached to the lens. Sometimes if the atropine alone does not dilate the pupil, another drug will be used that actively dilates the pupil. The corticosteroids are potent anti-inflammatory drugs. The main theoretical causes of uveitis involve an immune mediated inflammation--suppression of the ocular immune system is generally necessary to control uveitis. Despite this risk, the corticosteroids are necessary to control the inflammation associated with uveitis but if used on as ulcerated eye can lead to blindness. There are many different medications available to treat this condition, the medications that I use seem to work best for my horse, there are other drugs that cost more but these seem to work well for Girl. My Vet, Dr. Siegrist from the Illinois Equine Field Service has been a great help to Girl throughout the 26 years that he has been her vet.

Fly-Masks and Hoods

Fly masks work well as they block the sun yet allow air to circulate around the eye. I do have a racing hood with a solid eye piece that laces on but the eye is not allowed to breath causing a greater possibility to promote fungus. If the eye must be cover darker than the fly-mask it is best to cover the side of the mask with cloth. The best treatment in regards to light during a flare up is to leave the horse inside during the daylight hours and out at night. Another very important thing to remember is the stall must be kept clean.

Most important it is imperative that the diagnosis be made by a VETERINARIAN.

And that treatment be started as soon as possible.

The Indians called it moon blindness as it seemed to be tied to the cycle of the moon.

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This site was created in 1999-2012 by A. Olsen ęCopyright 1999-2012, A. Olsen. All Rights Reserved.
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