Eye Infections and Injuries in Horses

There are a range of infections from mild to very serious

Horse eye
Your horse's eyes should be clear, with perhaps only a small bit of tearing, which is normal. Andrew Bret Wallis/Digital Vision/Getty Images

Eye injuries and infections are common in horses. This is just one of the reasons you should check your horses —and not just from over the pasture fence — at least twice daily.

Untreated eye problems can become nasty very quickly. Minor problems can even result in blindness if left untreated. If the eye becomes badly infected, the structures of the eye can be eroded until the entire eye collapses.

But with prompt treatment, many eye problems can be brought under control within a few days. Sometimes a veterinarian should check the eye, but most treatment can be done by you, at home. 

What Do Eye Infections Look Like in Horses?

Your horse's eyes should be clear, bright, and the lids tight, with the inside of the lid pale pink and moist. Tearing should be minimal with perhaps only a droplet at the corner of the eye. Sometimes, if there is dust, dry air or​ wind, a horse’s eye might run a bit, just as yours would.

Treatment is necessary if:

  • An eyelid is cut or torn.
  • The lids are swollen.
  • Obvious damage to the eye itself.
  • There is a white film either over the whole eye or in spots.
  • The eye or any surrounding tissue, including the white sclera and lids, appear red and inflamed.
  • There are tears running down the horse's face which may indicate a torn or blocked tear duct.
  • Any other copious discharge other than a thin tear-like stream.
  • There are tumors growing on or around the lid.
  • In foals, turned under eyelids that cause the eyelashes to rub against the eye.

Types of Eye Infections in Horses

Just like humans, horses are prone to conjunctivitis, caused by irritation or bacteria getting in the eye. It presents in horses in a similar way: redness, swelling and oozing pus. This infection requires treatment with an antibiotic, usually drops or an ointment applied to the eye.

Recurring uvetis is another, much more serious eye infection in horses that can lead to blindness if left untreated. Also known as "moon blindness," this condition can be traced to two possible causes: infection with the Leptospirosis bacteria, or the Onchocerca cervicalis parasite. Most often in horses, Leptospirosis is the cause.

The signs of uvetis include squinting (indicating a sensitivity to light), cloudy eye, yellowing of the whites of the eye, chills, fever, lethargy, constricted pupils and eye spasms. If you notice any of these in your horse, take it to the veterinarian immediately: uvetis is fast-acting and requires aggressive, timely treatment with antibiotics.

The parasite Thelazia spp. is the cause of a nasty condition known as eye worms. This condition is passed from one animal to another via flies, and is most prevalent in cattle. A veterinarian will have to remove the worms from the horse's eye with surgical instruments (usually a forceps) while the animal is under sedation.

First Aid for Eye Injuries and Infections

If your horse has an eye injury or infection:

  • You should have salt or saline solution in your horse's first aid kit. Clean the area very gently with a saline solution. If you don't have one on hand (like the saline solution for contact lens wearers) you can make some yourself. The ratio is about 1/4 tsp. of table salt to a cup of boiled and cooled to lukewarm water. It should taste like tears.
  • Put a fly mask on the horse to keep flies off of the eye area.
  • If possible keep your horse in subdued light such as its stall until the veterinarian arrives.

Treatment for Serious Eye Issues

Rips and tears in the horse's eyelids should be attended to by a veterinarian so the lid can be stitched if necessary. The vet will also check for damage to the lens and anything that may be lodged in the eye (splinters, awns from grasses or grit). A vet can assess the overall health of the eye and may be able to see problems that aren't apparent to the untrained eye.

The veterinarian will probably give you an ointment or gel to apply to the eye. In some cases, he may draw a vial of the horse's blood and make a solution from it that you will irrigate the eye with. With all medications make sure that you follow the veterinarian's instructions to the letter and be scrupulously clean as you apply any dressings or ointments.

How You Can Help Your Horse Heal

Just because you see marked improvement within a few days, don't stop the medication until the full course is up. Stopping treatment before the infection or injury is completely healed can result in the infection flaring up again and possibly causing more damage. 

When working with a horse with an eye problem be aware that it may have obscured vision and be a little more jumpy than usual. Talk gently so you don't surprise your horse if you walk up on a 'blind side'.

Preventing Eye Injuries

Your horse's environment should be as dust free as possible. If hay is dusty, or bedding is very dry and dusty, dampen it or use other fodder or bedding. Make sure that sharp edges on water troughs, metal buildings, pipes or other obstacles are covered or inaccessible. Pound in or pull any old nails that may be protruding from fences or other structures.

Many injuries are caused when horses are playing or scraping, and this is almost unavoidable. Just take care to make your horse's home as safe as possible.