A corneal ulcer is a wound or sore on the surface of the eye. The cornea is the clear part of the eye in front of the iris and pupil of the eye. In an uncomplicated corneal ulcer, the outer or epithelial layer of the cornea is damaged or removed; in severe cases, the deep layer or stroma is exposed or damaged.
Signs and Symptoms
Corneal ulcers are painful. You may notice your pet squinting, keeping their eye closed, light sensitivity, excessive tearing or discharge from the eye, abnormal elevation of the third eyelid, redness of the eye, swelling of the eyelid, and/or rubbing at their eye.
Causes of an ulcer
A corneal ulcer can be caused by chemical irritants, dry eye, eyelid abnormalities/dysfunction, foreign material in the eye, glaucoma, infection, or trauma.
How is a corneal ulcer detected?
Most ulcers are detected after a fluorescein stain is applied to the eye, and the veterinarian uses an ophthalmoscope to see if the eye's surface absorbed the stain. If there is an area of stain uptake, that is an ulcer. A normal, healthy cornea will not uptake any stain. Some severe corneal ulcers can be seen with the naked eye.
When a corneal ulcer is detected, a veterinarian may do additional testing to determine the cause of the ulcer if it is not apparent. For example, they can test for dry eye with a Schirmer tear test and check eye pressure with tonometry. If a corneal ulcer is not healing appropriately, they may recommend doing a bacterial culture or cytology (looking at a small number of cells under the microscope).
Corneal Ulcer Treament
An uncomplicated corneal ulcer that only affects the outer layer of the cornea can be treated with pain medication and antibiotic eye drops several times a day for about a week. More complex or deeper corneal ulcers may need oral medication in addition to topical eye medication and may take several weeks to resolve. It is essential to follow up as often as your veterinarian recommends. Your veterinarian may refer you to a veterinary ophthalmologist if the ulcer is severe, complex, or not healing. Surgical intervention may be required if the ulcer is deep, complex, or chronic and not responding to medication, and it can take 2-3 months to fully heal.
Chronic, complex, or deep corneal ulcers may cause inflammation in the eye itself, referred to as uveitis. Uveitis can be treated with oral anti-inflammatories. However, eye drops containing anti-inflammatories can be very painful to a corneal ulcer and should generally be avoided.
Your veterinarian will likely recommend an Elizabethan or cone collar for your pet to wear during treatment. They must wear it at all times to prevent them from causing further trauma to their eye.
