Corneal Ulcers in Cats

A corneal ulcer is an open sore on the cornea, the clear front surface of your cat’s eye. The cornea helps protect the eye and focus light, so even a small injury can be very painful and can affect vision. In cats, ulcers may involve only the outer surface or extend deeper into the cornea. Deeper ulcers are more serious because they can weaken the eye and raise the risk of rupture.

Corneal ulcers are not something to watch at home for long. Cats often hide discomfort, but eye pain tends to show up as squinting, tearing, pawing at the eye, light sensitivity, or a cloudy appearance. Feline herpesvirus is a common underlying cause in cats, but trauma, foreign material, chemical irritation, eyelid abnormalities, and tear-film problems can also play a role.

Prompt veterinary care matters because ulcers can change fast. A superficial ulcer may heal quickly with medication and protection from self-trauma, while a deep or infected ulcer may need frequent rechecks, advanced medications, or surgery. The goal is not only to relieve pain, but also to protect vision and preserve the structure of the eye.

Your vet will start with a careful eye exam and a history of when the signs began, whether there was possible trauma, and whether your cat has had prior eye disease or feline herpesvirus flare-ups. Because cats with painful eyes may resist handling, your vet may use gentle restraint and specialized lights to examine the cornea, eyelids, and surrounding tissues.

A fluorescein stain test is one of the most important tools for diagnosing a corneal ulcer. A small amount of dye is placed on the eye, then rinsed away. The dye sticks to damaged corneal tissue, making the ulcer easier to see. This helps your vet confirm that an ulcer is present and get a sense of its size and depth.

If the ulcer is deep, chronic, infected-looking, or not healing as expected, your vet may recommend more testing. That can include checking tear production, looking for eyelid or eyelash abnormalities, evaluating for feline herpesvirus, or collecting samples for cytology or culture before certain medications are used. Cats with severe, melting, or very deep ulcers may need referral to a veterinary ophthalmologist.

Corneal ulcers in cats have several possible causes. Trauma is a major one. A claw scratch during play or a fight, rubbing the eye on a rough surface, or a foreign particle trapped under the eyelid can all damage the cornea. Chemical irritation, such as shampoo or dust exposure, can also injure the eye surface.

Infectious disease is another big factor, especially feline herpesvirus-1. In cats, herpesvirus is a common cause of recurrent eye disease and can lead to ulcers that heal slowly or come back over time. Secondary bacterial infection can complicate an ulcer and make it more serious. Some cats also develop ulcers because of eyelid abnormalities, abnormal eyelashes, poor tear production or tear quality, or trouble fully closing the eyelids.

Risk may be higher in outdoor cats, cats in multi-cat settings, and cats with a history of upper respiratory disease or chronic eye issues. Stress can contribute to herpesvirus flare-ups in carrier cats. Middle-aged or older cats with ulcers that seem to appear without obvious trauma may need a closer look for underlying corneal degeneration or other chronic eye disease.

Not every corneal ulcer can be prevented, but you can lower risk. Keeping cats indoors reduces exposure to fights, scratches, and environmental debris. Prompt care for conjunctivitis, upper respiratory flare-ups, and chronic eye discharge can also help, especially in cats with a history of feline herpesvirus.

Pay attention to recurring squinting, tearing, or one eye that never seems fully comfortable. Those patterns can point to an underlying issue such as herpesvirus, eyelid abnormalities, or tear-film problems that need management before an ulcer develops. If your cat has long facial hair or a flat face, regular eye checks at home are especially helpful.

Avoid putting human eye medications into your cat’s eye unless your vet specifically told you to use them. Some products, especially steroid-containing eye medications, can make certain corneal problems worse. If your cat gets shampoo, cleaning product, dust, or another irritant in the eye, flush only if your vet advises it and arrange prompt veterinary guidance.

The outlook depends on how deep the ulcer is, what caused it, whether infection is present, and how quickly treatment starts. Many superficial ulcers improve fast and may heal within a few days. More complex ulcers can take weeks, and herpesvirus-associated ulcers may be slower to heal or may recur later.

Rechecks are a big part of recovery. Your vet may want to recheck the eye within 2 to 3 days, because a corneal ulcer that is not improving quickly can become a more complex problem. If the ulcer deepens, starts melting, or involves more than half the corneal depth, the risk to vision and the eye itself rises, and advanced care may be needed.

Some cats heal with little lasting change, while others are left with a scar, pigment, or visible blood vessels in the cornea. That does not always mean poor vision, but it can affect clarity depending on the location. The best outcomes usually come from early treatment, careful medication use, preventing rubbing, and keeping every recommended recheck.