Corneal Ulcer

Corneal ulcers are a relatively common eye problem seen in veterinary medicine. The cornea is the clear shiny surface of the eye. It has three layers. The most superficial layer is the epithelium. Below the epithelium is the stroma, and the deepest layer is Descemet's membrane. Behind the cornea are the fluid, the lens, the nerves, and the muscle of the eye. If the cornea is penetrated, the liquid leaks out and vision is permanently lost. A corneal ulcer happens when one or more of the cornea’s three layers erode away. As the erosion gets deeper, the risk of penetration of the cornea and permanent blindness increases.
The most common cause of a corneal ulcer is trauma, either blunt like rubbing the eye with the paw or on the carpet or a laceration such as a cat scratch. Less common causes include viral infections, rolled eyelids, or problems with tear production. When a corneal ulcer occurs it causes a lot of pain. Animals may squint, tear, have reddened whites of the eye, or rub at the eye. Other signs include a white discoloration, a dark discoloration, or growth of blood vessels into the cornea.
Diagnosis is made by placing dye onto the eye and shining a special light over the eye. Only the middle layer of the cornea picks up dye. If the outer layer is damaged, the dye will stain the exposed middle layer of the cornea. Treatment varies with severity of damage. An Elizabethan collar is used to prevent further trauma from rubbing. Topical antibiotics and medicine for pain may be prescribed. If the ulcer is very deep, surgery may be recommended. Frequent re-checks are required to make sure that the cornea does not rupture and to make sure the eye heals completely. If your pet is “winking” at you, it is vital to have your pet checked for corneal ulcer. Not only will early treatment reduce the likelihood of complication but you will also decrease the amount of time your pet is in pain.