Eye Trauma in Horses
- Nov 1, 2010
Your horse greets you one morning with one eye held shut and tears running down the side of his face. He resists your attempts to get a closer look at the eye, so you can't tell if there's something embedded in it.
Eye injuries are fairly common in horses and can be serious, especially if neglected. They run the gamut from corneal injuries (e.g., superficial scratches, punctures, or a foreign body caught under an eyelid) to full-thickness eyelid lacerations to blunt trauma.
Have a veterinarian examine a horse with an eye injury as soon as possible to diagnose the problem, check for corneal ulcers, and determine the best course of treatment.
Steer Clear of Sharp Edges
Preventing eye injuries can be tricky, especially since horses rub their heads and eyes on any solid object available, especially during fly season. Make sure stalls are hazard-proofed to prevent eye injuries. "Stall hardware can snag an eyelid, and the biggest culprits are J-shaped hooks on water buckets," says Ann Dwyer, DVM, of Genesee Valley Equine Clinic, in Scottsville, N.Y. A simple preventive measure is to place electrical tape or duct tape over the handle hooks. Also look around the stall to see if anything else has a hook, protrusion, or sharp surface. Remove it or tape it up, and check wood surfaces for splinters.
Most eye injuries can be prevented with common sense. "Don't have a narrow opening in a stall or pasture that a horse might stick its head through or get it stuck. Fly masks are also helpful, to prevent eye irritations and infections," says Dwyer.
Even certain pasture plants can be culprits. "If there's burdock (a barbed pasture weed) in pastures, cut it down," she adds. "If a horse gets burrs stuck in the mane, don't leave them there. They can be difficult to remove, but using WD-40 or a silicone spray can help free the burrs more readily. If a horse gets a sore eye ¬after you've seen burdock in its mane, this might be a possible cause."
Richard McMullen, DVM, DrMedVet, CertEO, assistant professor of ophthalmology at North Carolina State University, warns against using hay nets or feedbags in stalls or trailers. If the bag is head level or higher, chaff (chopped straw or low-quality hay) and hay dust can get into the eyes. Horses like to grab and shake the bags, which can cause hay stems to scrape or poke eyes. To avoid these types of injuries, feed hay on the ground in stalls.
Eye Involvement: Don't Take it Lightly
Not all injuries can be prevented, however, and in the event your horse' s eye is involved, a same-day veterinary evaluation is recommended. McMullen says that even a superficial scratch can progress into something deeper, leading to penetration of the cornea from secondary infection. "It should be looked at by your veterinarian as soon as possible, to make sure it doesn't progress to something worse," he says. Corneal ulcers, for instance, are not to be underestimated in the horse; they can worsen quickly, but they are nearly always curable.
Recommended instances to call your vet for a same-day evaluation include:
- Eyelid snag or tear
- Holding the eye shut
- Squinting, in conjunction with tears or pus coming from the corner of the eye
- An eyeball that suddenly turns cloudy or a develops a white, yellow, or bluish area
- A painful eye; the horse resists handling
Dwyer adds that downward-pointing eyelashes are a subtle sign of trauma to the cornea. "If one side of the face has perky eyelashes, and the other side has eyelashes at half-mast, this is often the sign of an eye problem. This is especially important to look for in a horse that might have been on non-steroidal anti-inflammatory medications, which can mask some of the pain," she says.
Make sure you differentiate between a slightly irritated eye and a sore eye when describing the problem to your veterinarian. If one or both eyes are running tears, but the eyes are wide open, it's usually not indicative of major injury, and it's not as imperative that your veterinarian see the eye immediately. It's crucial to have an exam quickly, however, if the eye is partially open or if the horse doesn't like to have one eye handled because of soreness/sensitivity (but is fine with the other). As a rule of thumb, when in doubt call your veterinarian.
Choice of treatment for an eye injury depends on the extent of damage, which is why a veterinarian should evaluate the eye. While waiting for your veterinarian to arrive, don't try to rinse the eye with saline, advises McMullen. "If you try to rinse out a piece of foreign matter, you run the risk of pushing it into the conjunctiva (the delicate membrane that lines the eyelids) or dislodging it and causing it to go somewhere else it shouldn't be," he explains.
An injured eye is always painful, and as mentioned before, the horse might resist having it handled. Your veterinarian can sedate the horse if necessary, using a regional and topical anesthetic so that he or she can thoroughly examine the eye more easily.
"Choice of treatment will always depend on what is going on--whether there's blood in the eye, or (retinal) detachment, or a corneal ulcer," says Caryn Plummer, DVM, Dipl. ACVO, assistant professor of comparative ophthalmology at the University of Florida. "All of these situations need to be treated very differently. Many eyes that sustain trauma will have corneal insults as well as intraocular inflammation."
The veterinarian will prescribe treatment to decrease pain and combat infection, depending on the type of injury. "Treatment may involve use of systemic anti-inflammatories such as Banamine (flunixin meglumine), Plummer continues. "If there is no corneal ulceration (confirmed by the veterinarian), topical steroids and atropine may also be helpful." These might reduce inflammation and swelling that could further damage the eye.
Dwyer adds, "It is very important to follow the directions prescribed (for drug administration). Depending on location of the trauma, this might mean oral or injectable drugs (to treat trauma to skull or skin) or intensive (administered as often as every two hours) topical drugs if the injury is to the globe itself," says Dwyer.
Eyelid Lacerations Eyelid injuries should be repaired as soon as possible. Eyelids protect the eyes and spread moisture over the eyeballs to keep them from drying out. If there's a gap in the lid, corneal health will be compromised.
"These can sometimes be put back together even if they look horrendous," says Dwyer. "Never trim off a dangling piece, even if it's hanging by just a thread of tissue."
McMullen says the eyelid is so well vascularized that bringing the two pieces back together and suturing them appropriately will often enable the tear to heal. "Proper suturing is essential. Minor nicks may heal on their own without complications, but a larger laceration generally heals poorly, leaving the horse with an eyelid deformity that could cause corneal ulcerations later," he explains.
Blunt Trauma "Occasionally a horse will suffer enough blunt trauma to fracture part of the orbit--the bones around the eye," says Dwyer. This type of blow might occur from a kick or from a horse banging his head on a trailer.
If a horse has a tender, swollen eye, have a veterinarian examine it as soon as possible. "This area can be hard to X ray, and the veterinarian might use ultrasound," says Dwyer. Your veterinarian should refer severe cases, which are rare, to a specialist for surgery. However, if the bone is just cracked or if there's a small bone fragment, your veterinarian can usually remove any fragments before starting the horse on antibiotics and anti-inflammatory medication. Subsequently, monitor the horse carefully to make sure the eye improves with the prescribed treatment.
Corneal Injuries A veterinarian can locate foreign material or a corneal scratch using a fluorescein dye in the eye to highlight subtle corneal defects.
"Knowing whether or not there is a scratch on the cornea is very important," explains Plummer. "If you treat an eye with a topical steroid to deal with the inflammation, this can worsen the corneal disease. This could delay healing or possibly lead to infection.
"Whenever there's an insult to the eye from organic material, the risk for infection is much greater," she says. "There are bacteria and fungi everywhere, and these may be carried into the eye with the foreign material. These can complicate or cause a noninfected ulcer to become infected."
Again, timely treatment is crucial. "Long-term consequences of ocular trauma that is not treated promptly can include permanent blindness, cataract formation (which can cause vision deficits) and long-term chronic inflammation that causes pain or discomfort--affecting the animal's performance and quality of life," says Plummer. "Globes with severe trauma may develop glaucoma or may shrink. There's so much damage that structures within the eye that produce the fluid that keeps it in its normal shape shut down, and the eye becomes small and nonfunctional."
According to Plummer, neglected injuries or significant trauma could lead to persistent scarring and edema in the cornea. "This could be potentially blinding, or make the horse prone to recurring corneal ulcers. These problems not only impair vision and performance, but also affect quality of life. Ocular pain is like no other. The eye is uniquely innervated; the cornea is one of the most densely innervated structures in the entire body, with more nerve endings," she says.
"Surgical intervention is indicated for deep lesions or full-thickness penetrating injuries," says McMullen. "If caught early (even if they seem catastrophic) they can often be corrected with corneal transplants or grafting procedures (conjunctival or amniotic grafting) or, in some cases--as a last resort--removal of the globe." Many horses do well after they adapt to loss of sight in one eye.
Your veterinarian should give instructions for applying medication. Usually the medication will be an ointment that you apply to the inside of the eyelid. Make sure your fingernails are short, and wash your hands thoroughly beforehand.
Dwyer coaches owners on a technique to make ointment application easier. "I show the owner where the orbital rim is (the bone above the eyeball) and have them feel it. Then I show them where the crease is, on the upper eyelid, and tell them to touch that wrinkle with their first finger. Then lift the eyelid and let that finger push into the groove between the bony orbit and the eyeball globe, resting the finger that's prying open the eye on that bony rim," she says.
"Use the other hand to apply medication from the tube of ointment. Sometimes a person might prefer to fold a strip of oint-ment over the inside of the lid (using a very clean finger with short fingernail), but it's better to apply it with the tube if you can," she adds. "You don't have to get the ointment onto the lesion. You just have to get it over the edge of the lid. It will melt and spread over the entire eyeball surface." It always helps if there are two people--one to hold the horse and one to apply the medication.
McMullen gives another tip for applying eye ointment: "If you put a little pressure in the fold of the upper eyelid with the in-dex finger as you open the eye, the third eyelid comes into view. You can then apply a little ointment in the corner of the eye where the third eyelid is. When you let go of the eyelid and the third eyelid retracts, the ointment will go down into the ventral conjunctival sac where it will melt and be distributed over the cornea."
For a how-to video about applying eye ointment, visit www.TheHorse.com/Video.aspx?vID=410.
"If the horse is head shy and the injury is serious, we avoid risk of injury to the horse or person by putting in a lavage tube," says Dwyer. "This small silicone tube is surgically inserted into the upper or lower eyelid. It's a long catheter that runs from the eyelid over the poll and down along the mane to the withers. An injection port is attached to the mane so the medication can be injected through the tube and dripped onto the surface of the eye several times a day."
About the Author
Heather Smith Thomas ranches with her husband near Salmon, Idaho, raising cattle and a few horses. She has a B.A. in English and history from University of Puget Sound (1966). She has raised and trained horses for 50 years, and has been writing freelance articles and books nearly that long, publishing 20 books and more than 9,000 articles for horse and livestock publications. Some of her books include Understanding Equine Hoof Care, The Horse Conformation Handbook, Care and Management of Horses, Storey's Guide to Raising Horses and Storey's Guide to Training Horses. Besides having her own blog, www.heathersmiththomas.blogspot.com, she writes a biweekly blog at http://insidestorey.blogspot.com that comes out on Tuesdays.