The Horse:Your Guide To Equine Health Care provides monthly equine health care information to horse owners, breeders, veterinarians, barn/farm managers, trainer/riding instructors, and others involved in the hands-on care of the horse.
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18 TheHorse.com THE HORSE October 2015 pain accompanied by excessive tearing and a strong urge to keep the eye shut." What to do Because the horse is experi- encing pain and discomfort, it is often dif- ficult for owners to distinguish the extent of the scratch or what the injury even is in the first place. Bourne says that's why it's important to call your veterinarian and give him or her a detailed description of the clinical signs you can see and ask for his or her professional opinion about diagnosis and treatment. She says simple corneal ulcers are typically easy to treat and heal if caught promptly, but if they go undiagnosed or misdiagnosed for a long period of time, they can lead to more serious problems, such as bacterial and/or fungal infections. To help keep the horse comfortable until the veterinarian arrives, bring him inside or put a fly mask on him to keep sunlight, dirt, and insects off the ulcerated eye. If the horse will allow it, she says the veteri- narian might also suggest applying a cold compress to provide pain relief. Diagnosis Bourne says most horses need to be sedated so the veterinarian can get a better look at the eye. Veterinar- ians might also choose to perform nerve blocks around the eye to counteract the horse's instinct to hold it tightly shut. She says that occasionally you can see obvi- ous signs of an ulcer (e.g., cloudy spots) or, in severe cases, a gouge to the surface of the eye. But most of the time a veteri- narian must apply a fluorescein stain that adheres to the surface of the eye beneath defects, so they can see them and make a definitive diagnosis. Treatment Practitioners usually apply topical antibiotics to the eye to prevent infection, accompanied by non-steroidal anti-inflammatories such as phenylbu- tazone (Bute) or flunixin meglamine (Banamine) to control the pain. Do not administer steroids to reduce the inflam- mation, as these can actually worsen the disease, delay healing, or possibly lead to infection, cautions Ann Dwyer, DVM, of Genesee Valley Equine Clinic, in Scotts- ville, New York. Bourne says veterinarians might also prescribe a dilating agent if the iris is spasming as a pain response, which is painful in and of itself. To speed healing many veterinarians administer topical autogenous serum—derived from the horse itself—to reduce tear film and cor- neal protease activity (enzymes breaking proteins down into amino acids). A fly mask can be a very useful tool to protect the eye from bright light and debris while it heals. Recovery "If the ulcer is minor, the horse is typically much better within 24 hours of starting treatment," Bourne says. "Most corneal ulcers in an otherwise healthy horse will heal completely in three to seven days. However, if the ulcer has been going untreated or mistreated for several days or longer, the recovery and treatment period can be much more complicated." 2 Foreign Body Injuries Anything that is not supposed to be in or around the globe falls into this category. This could be hay, grass, wood, thorns, burrs, seeds, etc. "The most common foreign bodies I see in the Northeast are burdock pappus bristles," says Dwyer. The foreign body can be floating across the eyeball, embedded in the lids or along the sides of the eye, or in a worst case scenario, it impales the eye itself. It is very common for a foreign body to cause a corneal ulcer. Clinical signs Most of the time you will not be able to see an ocular foreign body because of the excessive tearing and swelling. If the foreign body has impaled the eye, Bourne says you might be able to see it, but you should not remove it. She says removing the foreign body improp- erly can cause the structure of the eye to collapse, which is very serious and might result in eye loss. What to do Because the clinical signs for many of the injuries we discuss in this article are the same (tearing, swelling, pain, etc.), it's important to have a profes- sional diagnose the horse. In the case of a foreign body, especially if you can see the object, remain calm and keep the horse calm. Bourne says it also is important to keep the horse from rubbing his eye, which can damage it further. Diagnosis Similar to corneal ulcer treatment, veterinarians often sedate the horse and use nerve blocks around the eye so they can properly assess and locate the foreign body. Treatment For minor foreign body injuries, usually removing the irritant is the only necessary step, Bourne says. If the object has caused a corneal ulcer, the veterinarian will need to treat it as out- lined above. Depending on the severity 5 Common EYE Injuries Fluorescein stain adheres to the surface of the eye beneath most defects, allowing the veterinarian to visualize and diagnose corneal ulcers. DUSTY PERIN Eyes with corneal ulcers are uncomfortable and typically sensitive to touch and light. COURTESY DR. RACHEL BOURNE