Common Eye Problems in Horses

Horses are generally sturdy, healthy animals, but like any other creature, they do have their problems that will occur from time to time. Good equine care includes daily checks of your horse to make sure he has not obtained any injuries or become sick. One area horse owners often neglect, simply because they don’t think it will be a problem, is a horse’s eyes. Surprisingly, eye injuries and infections are common in horses.  One reason horses suffer from eye problems so often is due to the anatomy of their eyes. If any of these eye conditions are left untreated, even minor problems can result in blindness.

It is important to remember that even minor eye problems in a horse can become serious very, very quickly, so do not put off treatment once you have discovered there is a problem. If your horses eyes are clear, clean and bright, which includes nice tight eyelids with no drooping, and a healthy pink color on the inside of the lid, then your horse is doing well. The eyes should be moist, and very minimal tearing is normal. However,  if any of the following conditions exist, there is a problem that will require treatment:

  • Excessive watering of the eye – tears actually running down the horse’s face. There may be a tear duct that is blocked or injured because the horse got poked in the eye when it bent down to eat grass.
  • Abnormal discharge – any color, thick or thin, which would be the manifestation of some sort of infection.
  • Inflammation of the eye or tissue surrounding it – when the lids appear red and sore instead of a healthy pink color. A white film covering the eye or in spots on the eye is also abnormal.
  • Swollen lids, or an eyelid that is cut or torn.
  • Any sort of growth or lump on the eyelid, as well as any obvious damage to the eye.
  • Eyelids that are turned under (which would cause the eyelashes to rub against the eye), which occurs mostly in young foals.


If you are uncertain about a condition, or suspect there may be a problem, do not hesitate to contact your veterinarian for a thorough examination of your horse’s eye. Any medication that is necessary will be prescribed immediately. Below are some common eye problems and how they are treated.

  1. Corneal Ulcer: one of the most common problems involving the cornea (outer surface of the eye which protects the deeper surfaces and eye structures) has been scratched or torn. This condition is characterized by excessive squinting and/or tearing or watering of the yes, and often accompanied by a cloudy spot on the surface of the eye. Your veterinarian will stain the horse’s eye using flourescein which will adhere to the injured area of the cornea. Treatment involves applying an antibiotic ointment to the affected eye. When this problem is discovered early and treated immediately, it usually heals within 7-10 days. If a corneal ulcer is left untreated, is can become serious enough to rupture your horse’s eye, and may even require removal.
  2. ERU or equine recurrent uveitis (also known as moon blindness): one of the most common causes of blindness in horses. This condition is when the uveal tract, or middle layer of the horse’s eye, becomes inflamed. It should be noted that this is a chronic condition, which means it is a problem for a long time, and also a very painful condition. ERU is generally caused by a bacterial infection or leptospira infection (which is a small organism or parasite). Symptoms of this condition are similar to others, which include tearing, redness with swelling, and a sensitivity to light. Treatment includes topical and oral medications to control the condition. It is important to learn to recognize the signs of this once your horse has been diagnosed, so you will be able to treat flare-ups quickly. Remember, this is a “chronic” condition, so it will not go away, but can be controlled with proper care.
  3. Conjunctivitis: the lining of the eyelids to become inflamed. It may be  caused by bacteria, parasites, fungus or a viral infection. This condition is also commonly known as “pink eye”. Depending on what has caused the inflammation, the treatment could include topical antibiotic ointment to the eye, a dewormer if the cause is parasitic, and possibly even surgery if the condition is too advanced for a topical remedy. Use of a fly mask during treatment can provide protection to your horse’s eye while it heals, as it helps shade the eye and keep face flies from attacking the infected area.
  4. SCC or squamous cell carcinoma: a tumor of the horse’s eye. Generally these occur in older horses. This condition is the result of long-term exposure to the sun’s UV rays, and a lack of pigment around the eyes. Lighter colored horses, such as white, gray or palominos, are affected more often. This problem manifests itself by the appearance of an growth in or near the eye. Diagnosis is confirmed by a biopsy of the affected area with treatment including surgical removal, radiation, laser removal or a combination of these methods. The size and location of the tumor will help to determine which treatment is chosen. If this condition is left untreated, it can spread to other areas of the horse’s body such such as the lymph  nodes, salivary glands or even the lungs.
  5. An obstructed tear duct, which runs from the horse’s nostril to the corner of their eye, can become blocked. Symptoms include a thick discharge which can be white or yellow, and seen in one eye or both. An infection is generally what causes the blockage, and it's often spread by face flies. A veterinarian can usually flush the duct successfully with saline to unblock it; however, on some occasions this may require a more involved treatment. Some horse’s are prone to this condition, so if this has occurred, keep an eye out for future occurrences so they can be treated quickly.


As soon as you discover an injury or problem with your horse’s eyes, you should take steps to minimize the discomfort and further injury. Here are some helpful tips:

Put a fly mask on your horse to keep face flies off the eyes.

  • Whenever possible, place your horse in a shaded area to reduce any discomfort bright light may be causing, while you wait for the veterinarian.
  • When a specific treatment has been prescribed by your veterinarian, DO NOT stop until all medication has been given, even if your horse seems to be fine beforehand. Treatments that are stopped before completion can lead to flare-ups.
  • Cleanliness is absolutely required, so make sure you are scrupulous in washing your hands when you handle your horse, and keeping him as clean as possible. This is a good practice before an injury or infection and should already be the normal part of horse handling, which will also help reduce such occurrences.


Although it is impossible to completely prevent injuries and infections, there are some things you can do to help minimize the possible threats:

  1. Keep your horse’s stall and living area free of excess dust and dirt.
  2. Regularly check watering and feed troughs to make sure the edges are smooth, and all jagged edges or sharp corners are covered, or even better rounded.
  3. Obviously pipes and other obstacles that barns and stalls may require to function cannot be removed or eliminated, but they can be covered and access restricted.
  4. Check barns, stalls and fences for nails that have popped up or backed out of their holes, and either pound them in, or replace if needed. A scratch with an old nail can be very dangerous.
  5. Regularly examine all fences, and repair immediately any cracked, splintered or broken boards or wiring. It is important to keep all surfaces your horse may come in contact with as smooth as possible. Remember a horse’s face is the first thing to come in contact with any surface.

Note that a horse suffering from any eye injury will have discomfort, so his temperament  will also change. Be patient and keep him as calm as possible, as he will be more skiddish than usual.

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