A scratch of the eye's cornea (clear surface portion of the eye) is quite painful and can cause tearing, swelling of the eyelids, closing of the eyelids, and constriction of the pupil. Such scratches or a long-standing irritation of the cornea can lead to formation of an ulcer, or erosion of the cornea. Generally, accidental poking of the eye causes corneal ulcers, but occasionally other causes (ingrown eyelashes, splinters, deep summer sore infections, dysfunction of the eyelids) can cause corneal ulcers. These problems should be ruled out by examination. Routine traumatic corneal ulcers heal in a few days. Progression of healing is indicated by reduced pain and swelling, then possibly a few days of corneal cloudiness (edema) around the ulcer site, leading to a normal cornea.
Your veterinarian will use several medications to treat the eye. A medication that dilates the eye, such as atropine, is applied to dilate the pupils. This helps relieve pain and keeps the pupil open to help prevent internal damage to the eye. Shine a light in your horse's eye and compare the pupil of the treated eye with the pupil of the normal eye. In the eye treated with atropine, the pupil is large and round. Remember, with dilation of the pupil, your horse's vision will be temporarily abnormal. Consider this when riding and with extensive trail rides, new close quarters, jumping, etc. The pupil may remain dilated for several days after treatment. Antibiotic medication prevents infection and allows natural healing of the ulcer. An important point in treatment of the eye is to always consult a veterinarian before applying any medication to your horse's eye to treat an eye problem. Some medications contain steroids that can inhibit corneal healing and can possibly cause the loss of the eye.
Non-steroidal anti-inflammatory drugs (NSAID) are also used. These drugs reduce the inflammation that occurs in the eye from the injury. Flunixin meglumine (Banamine), Phenylbutazone or more frequently known as "Bute" and aspirin are the most commonly used NSAID for the eye. The one we use and the duration of therapy depends on the degree of inflammation and how the horse responds to the therapy.
Some other nursing care things can be done to help the horse are hot packing and protecting the eye with either a fly mask or an eye cup with hood. To hot pack, soak a towel or washcloth in water as hot as your hand can tolerate, and apply it over the eye. This is soothing and can reduce resistance to opening of the eyelid for application of medication. Discourage your horse from rubbing its eye. If your horse persists in rubbing its eye, fashion a patch or cup to protect the eye.
There are several things to watch for that would require your veterinarian to recheck the horse. If the eyelids have not re-opened in 2 days, if there is significant whitening of the cornea develops, if the blue-white haze of the cornea does not disappear within 6 days, or if your horse persists in rubbing its eye. Also, call if you are unsure if your horse's eye is healing properly, if you cannot apply the medication to your horse's eye as often as directed, or if you have any questions concerning corneal ulcers.
Remember that medical conditions of the eye can lead to blindness if not handled in the proper manner. Call your veterinarian with any eye conditions that are not normal. Prompt and proper attention with diligent nursing care can be the difference between an eye that is blind and one that is functioning well.