Photos courtesy of Long Beach Animal Hospital (LBAH)
Corneal ulcers, which are open sores on the cornea that can be caused by bacterial or viral infection, need antibiotics to control the infection and let the cornea heal. These antibiotics come in the form of drops or ointment. They are given at least two or three times every day until the cornea is completely healed and there is no update in the fluorescein dye test used to identify foreign bodies in the eye. This same medication lubricates and protects the cornea.
Corneal ulcers are painful because of the sensitive nerve endings in the eye. Ulcers also cause the iris to spasm, adding to the pain. Topical atropine medication is put into the eye to relax the iris muscle and greatly reduce the pain. Occasionally, oral-pain medication is used to control the pain.
This is conjunctivitis, an inflammation of the tissues surrounding the eye. The cause can be minor or major, but an eye that looks like this one needs to be checked and treated immediately.
Topical cortisone, a great medication to minimize the conjunctivitis that is sometimes associated with a corneal ulcer, should not be used in most cases until the fluorescein dye indicates the ulcer is healed. Doing so might delay the healing of the cornea.
The use of an Elizabethan collar—you may know them as e-collars—is necessary to prevent self-trauma while the eye is healing, since rubbing or scratching at the eye can make it worse. It should stay on until the eye is completely healed.
Fortunately, most superficial corneal ulcers heal well with the consistent use of eye medication and the prevention of trauma with an e-collar. Some ulcers do not heal and get worse, possibly resulting in erosion all the way through the eye. This known as a descemetocele, a serious condition consisting of an erosion passing through the levels of the eye structure to the Descemet's membrane, the innermost level of the eye (see “Anatomy of the Cornea” in the previous The Vet Is In). This eye is at risk for complete penetration of the ulcer into the eye and subsequent rupture of the fluid of the eye to the outside, with complete loss of the eye.
The cloudy cornea on this cat’s right eye is the result of an untreated corneal ulcer.
If a corneal ulcer is not healing, additional therapy is needed. Dead corneal tissue along the edges can be removed with a cotton swab and special disinfectant. Most of the time, this can be accomplished with just a topical anesthetic. When this does not work, a conjunctival flap can be utilized. In this procedure, a tiny piece of the conjunctiva—the mucous membrane covering the front of the eye and lining the inside of the eyelids—with blood supply still intact, can be placed over the ulcer using fine sutures.
Additional treatment involves the use of topical autologous serum. This serum, which comes from the bloodstream, can counteract the enzymes from the inflammatory process that is dissolving the cornea.
Corneal stem cells have been used with some success in humans but are not yet used in veterinary medicine. These more advanced treatments are usually performed by a veterinary ophthalmologist.
Immediate treatment for any eye problem in animals is important. Do not delay an exam if your pet has any symptoms of squinting, redness, discharge or rubbing of the eye. There may or may not be an ulcer present, but animals with irritated eyes tend to do a lot of rubbing and scratching, and might cause a corneal ulcer. It’s best to treat the problem before it gets to the corneal ulcer stage.