A corneal ulcer is the disruption or loss of the corneal epithelium (the outer cells of the cornea). This condition is usually painful and may cause irritation to the conjunctiva as well. There are three forms of ulcers. The first, called superficial, affects only the outermost layers of the cornea, such as the epithelium. The second type, a shallow-moderate ulcer, can affect up to half of the stroma. The final type is a deep ulcer which can affect over half of the stroma, and if left untreated can cause the eye to collapse.
What are the causes?
There are a variety of causes of corneal ulcers; scrapes or abrasions to the cornea due to trauma, feline HPV virus, dry eye disease, or facial hairs rubbing on the cornea.
What are the symptoms?
Corneal ulcers are usually painful, so most owners will notice their pet excessively rubbing their eyes. Squinting, increased tear production, and sometimes either a yellow or greenish discharge from the eyes are also symptoms. Redness to the conjunctiva may be noted as well.
How is it diagnosed?
If any of the above symptoms are noted, an exam with an ophthalmologist should be scheduled. During the exam, the eye will be tested for adequate tear production and high eye pressures. The eye will also be stained with a fluorescein stain that will adhere to the ulcer and turn green under the blue light of the slit lamp.
How is it treated?
Once an underlying cause for the ulcer is identified a treatment plan will be recommended by the ophthalmologist. Normally, eye drops will be prescribed to help treat the pain and inflammation in the eye. If there is an underlying cause such as dry eye, there will also be medication used to treat that issue as well. If the ulcer is deep and is compromising the stability of the eye, surgery may be recommended. A conjunctival or corneal graft is often used to cover a deep ulcer until the area can heal, along with a tarsorphy procedure which keeps the eye slightly closed to protect the cornea and the graft until they are healed. Frequent rechecks will be needed initially to make sure the eye heals properly.