The cornea is the clear membrane that covers the front of the eye. It's composed of collagen and protects the pupil and iris. The cornea is also required for light refraction, which ensures light entering the eye reaches the retina at the back of the eye at the correct angle for clear vision. Your horse can get a corneal ulcer as a result of trauma to the eye, such as rough contact with another horse, a foreign object or grit getting into the eye and scratching the outer layer of corneal cells. A bacterial or fungal eye infection can also cause an ulcer to develop on the cornea.
If left untreated, a corneal ulcer can damage your horse's sight by allowing bacteria to enter the eye and infect other parts of the eye. Scar tissue can also develop around the ulcer, and this can cause visual impairment by preventing the cornea from refracting light effectively. Here's what you need to know about corneal ulcers in horses:
Common symptoms of a corneal ulcer include redness and inflammation around the eye, a clear or cloudy discharge and the appearance of blood vessels on the cornea. If left untreated, your horse may experience clouding over of the corneal surface and eye pain, which may present as trying to keep the eye closed. Pain of any sort can lead to loss of appetite in horses, so be mindful of this when assessing your horse's condition.
Diagnosis And Treatment
Your vet can diagnose a corneal ulcer in your horse by applying fluorescein stain to the eye and using an ophthalmoscope to magnify the anterior section of the eye. The stain is a harmless dye that's applied as eye drops and highlights damaged tissue. Additionally, the vet will swab the eye to check for the presence of a specific fungus or bacteria.
In order to allow your horse's eye to heal, it should not be exposed to light. Instead, allow the eye to rest by using blinders or shades or by keeping your horse inside. If fungus or bacteria are found in the ulcer, your vet will prescribe antibiotics or a topical anti-fungal. Anti-inflammatories and steroids can also be used to bring down the swelling, which will promote healing, and your vet will show you how to clean your horse's eye with saline while the eye is healing. If scar tissue has developed around the ulcer, this may need to be surgically removed to preserve your horse's sight.
If you suspect your horse has a corneal ulcer, or if you're concerned about their eye health, schedule an appointment with a vet as soon as possible.