Written by: Ashley Whitehead, DVM, BSc, DVSc, DACVIM

Learn how to administer ophthalmic medications confidently and efficiently.

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Although not quite as dramatic as a gushing wound, finding your horse with a swollen eye can be scary. Ocular problems are painful and should always be considered an emergency. In literally the blink of an eye, what may seem like a minor irritation can become disastrous and may even compromise your horse’s sight.

Prompt veterinary attention is required if you suspect your horse has a problem with his eye or surrounding tissue. Eye conditions begin with any of the following signs: excessive tearing, squinting, swelling, haziness or whiteness of the eye, white spots on the cornea or even itchiness.

After your vet has examined your horse’s eyes, she or he will generally prescribe an ophthalmic medication. These medications are usually topical, meaning that they are placed onto the eye and penetrate into the superficial tissues to work their magic. This article is intended to help you administer the medications your veterinarian may recommend.

The most commonly prescribed ophthalmic medications are usually in an ointment preparation. Other preparations include liquids, which may be administered in a dropper, squeeze bottle or in a syringe.

Eye medication usually requires multiple daily applications since prolonged contact time with the surface of the eye (cornea) is required and, unfortunately, the constant production of tears and normal blinking wipes it away over time.

Preparation and Safety

Applying eye medications can be difficult, and it may take some time to determine the safest and most efficient method of delivering the medication onto your horse’s eye.

Many horses do not tolerate the application of eye medications and may strike with their forelimbs or, more frequently, throw their heads around in an attempt to thwart their owners’ well-intentioned medication application.

Keep an eye on your horse’s body language and be prepared to move out of harm’s way. Having an experienced handler available can make the task safer and quicker. Both you and the handler should stand on the same side while applying the medication, although some horses may still require a nose twitch or distracting pinch of the skin on the neck during the procedure.

Positive reinforcement with treats immediately after the medication has been administered can also be helpful.

I like to accustom my horses to being touched around the eyes during regular grooming rituals; by gently opening their eyelids and reinforcing good behaviour with praise and sometimes treats, my horses learn to be comfortable with having my hands around their eyes. If I only approached this sensitive area during emergencies, my horses would understandably fear being poked in the eye and quickly learn to resist.

Cleanliness

Ophthalmic ointments will usually come in a small tube with a thin tip for easy application. It is extremely important that the end of the tube not touch the eye or any other surface – including your fingers – as this will contaminate the contents. Bacteria and fungus can grow on the surface of the tube and can easily cause a secondary infection, often a much more serious condition than the original complaint.

I recommend that you wear clean surgical gloves whenever handling eye medications and ensure the plastic cap is replaced and secured immediately after dispensing the medication.

Also, depending on your horse’s condition, you may be administering one or more medications. Be sure to confirm with your veterinarian if multiple medications may be applied simultaneously, as staggered times are sometimes required to allow for proper absorption.

ADMINISTERING EYE MEDS – OPTION 1

1. Stand on the side of the horse’s head facing the eye you are going to medicate.

2. Using the hand closest to the horse’s nose (left hand when you are treating the left eye), place the heel of your palm near the inside corner of the horse’s eye.

3. Use your index finger and thumb to slightly part the lids of the eye. As the lids part, the lower lid should move away from the eye ball creating a small gap. As an alternative to parting the lids, gently pull out the lower eyelids using the lower eye lashes. Some horses will tolerate this method over parting the lids. This is the ideal location to dispense the medication. The natural blinking motion of the horse’s third eyelid will disperse the medication across the surface of the eye.

4. Using your other hand, place the heel of the palm on the horse’s head near the outside of the eye while holding on to the tube of ointment between your index finger and thumb.

5. Hold the tube so that its end is pointing forward towards the inside corner of the eye. This helps reduce the risk of touching the tip of the tube to any of the eye structures. Also, if the horse throws his head, you will be less likely to poke his eye.

6. Starting at the inside corner of the eye, gently squeeze the tube and dispense a small strip of ointment into the small gap between the eye and the lower lid. Your vet will indicate the exact amount of medication to apply, which is usually between a 0.5cm and 1.5cm strip. Again, remember not to touch the tip of the tube to any of the eye structures.

7. Allow the lids to close.

8. You can gently massage the lower eyelid to help disperse the ointment. In most cases however, the blinking motion will adequately spread the medication.

Alternate Method

1. Wearing a clean pair of gloves, apply the medication to the tip of your index finger on your dispensing hand (right hand for applying medication to the horse’s left eye) prior to approaching the horse.

2. Follow steps 1, 2 and 3 from the first method.

3. Using the hand with the medication (dispensing hand), place the heel of the palm on the horse’s head to the outside of the eye.

4. Wipe medication from your index finger into the gap between the eye and the lower eyelid; the edge of the eyelid acts like a scraper to remove the medication from your finger. Try to apply the medication close to the inside corner of the eye. Do not wipe the medication onto the surface of the eyeball (cornea) as you may cause damage to the eye.

OPTION 2

While I do prefer this second option for most horses, it requires additional supplies.
1. Wearing gloves, remove the plunger from a 1ml syringe.

2. Squeeze the required amount of ophthalmic ointment into the syringe and replace the plunger.

3. Stand on the side of the horse’s head facing the eye you are going to medicate.

4. Using the hand with the medication (dispensing hand) place the heel of the palm on the horse’s head to the outside of the eye.

5. Insert the tip of the syringe into the inside corner of the eye between the eyelids and pointing towards the horse’s nose.

6. Gently, push the plunger to dispense the ointment.

7. The horse’s third eyelid that is situated in the inside corner will blink and immediately disperse the medication.

8. Discard the syringe. This is very important as the tip has now been contaminated and should never be reused.

Leftover Medication Caution

Many horse owners save that last few squirts of ophthalmic ointment in case their horse has another eye emergency. This is not a practice I recommend for the following reasons:

  • The medication may be the wrong type of medication for your horse’s next eye issue. This is especially true if the medication contains a steroid. If a steroid is applied to an eye with an ulcer, for example, the ulcer will quickly progress and cause extreme damage to the eye within only one or two applications.
  • The tube may be contaminated. With time, organisms will grow and flourish and will introduce a significant amount of bacteria or fungi the next time used.
  • Over time, some of the ointments may separate or no longer provide active ingredients.

Other Considerations

Ophthalmic ointments can make the surface of the eye more sticky than usual. It is important to keep the horse in an area where he is not exposed to dust of any kind. Also, feeding from hay nets and racks should be avoided since the horse’s eyes are at increased risk of having hay bits becoming stuck to the sticky ocular surface.

When the weather is warm, ophthalmic ointments may melt slightly and become runny, which will make application more difficult. Keep the medication in a cool area, but do not refrigerate unless your vet indicates that this is acceptable, as some medications should not be kept at lower temperatures.

If you struggle and find yourself unable to adequately or reliably apply the ophthalmic medication, contact your vet sooner rather than later. Your horse will only become more resistant with each application, and in such circumstances there are other forms of some medications available. Another alternative your vet may recommend is placement of a subpalpebral lavage system. This is a tubing system that gets inserted through the eyelid and extends down the horse’s neck. The medication is injected through the tubing and exits under the eyelid bathing the eye. This eliminates the need to pry open the eyelids to medicate your horse.

Every vet and horse owner will have his or her own tricks for applying eye medications and, in the end, all that matters is that the appropriate amount of eye medication is applied to the surface of the eye. It is also extremely important that you do not contaminate the eye or the medication tube and that you do not cause trauma to the surface of the eye by poking, scraping or scratching with the tube or your finger or finger nails.