Corneal Ulcers

Blog by Dr. Jamie Senthirajah


The cornea is the outer layer of the eye that consists of many sub-layers which provides a barrier to protect the eye and aids in vision. Despite the cornea acting as protection, it can still be damaged relatively easily.

Clinical Signs

Patients with corneal ulcers often have conjunctivitis (inflammation of the lining of the inner aspect of the eyelids), edema/swelling of the eye, tearing or discharge, or pain. Causes of corneal ulcers can vary, but often the culprit is trauma from running into something or even self-trauma such as allergies, animal attacks, a foreign body, infections, or chemicals such as detergents.


To diagnose a corneal ulcer, we perform a test called a fluorescein stain test. In this test, we apply a green stain onto the eye. If the cornea is intact, the eye will not uptake the stain. If there is a defect in the cornea, the exposed collagen will uptake the stain and will show up as a green area with the aid of an ultraviolet light.


Most corneal ulcers are at risk of becoming infected with bacteria. Because of this, if a corneal ulcer is noted, an antibiotic ointment or drop for the eyes will be prescribed. This medication will likely need to be applied at least three times daily, pain medications may also be prescribed if needed. An Elizabethan collar (E-collar) may be recommended if your pet is prone to scratching or irritating the already compromised eye.


Most ulcers will heal well with medications and time. A recheck one week after starting medications will be needed to determine if the corneal ulcer has healed. If it has, no further treatment is necessary. However, some uncomplicated ulcers can take about two weeks of treatment. If the ulcer is still present after that time, further treatment with a veterinary ophthalmologist may be indicated.

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