Corneal ulcers in cats are painful sores on the surface of the eye. They can happen in cats of all ages and types. But short-faced (brachycephalic) breeds and cats with other eye problems are most at risk.

Corneal ulcers or eye ulcers result from damage to the outermost layer that forms the outermost layer of the eye. Trauma or disease can be triggers, and severity depends on depth of the ulcer and the eye’s ability to heal. With prompt identification and treatment, most eye ulcers heal within a week. Untreated or non-healing ulcers may penetrate the eye, potentially causing blindness or even loss of the eyeball. Talk to a vet for advice as soon as you notice anything wrong with your cat’s eyes.

What are corneal ulcers in cats?

The cornea is the clear window at the front of the eye. It’s very thin, less than 1 mm thick. But it’s strong and plays a vital role in allowing light into the eye, while also protecting deeper delicate structures. It's made up of 3 layers. The cornea also has lots of nerve endings, so it's very sensitive.

Corneal ulcers:

• Are open sores, like craters, on the surface of the eye.

• Develop when infection, trauma or inflammation destroys the outermost layers of the cornea.

• May eventually penetrate all the way through the deepest layers of the cornea, allowing infection and inflammation into the back of the eye.

Causes of corneal ulcers include:

• Scratches: fight injuries

• Foreign bodies in the eye: thorns, grass seeds, splinters, grit, sand

• Eyelid abnormalities: in turned eyelids

• Extra eyelashes or hairs under the eyelid

• Infections: viral or bacterial conjunctivitis, particularly Feline Herpes virus

• Dry eye

Symptoms of corneal ulcers in cats

Eye ulcers are very painful due to all the sensitive nerve endings present on the cornea.

Symptoms include:

• Having a weepy eye

• Blinking more

• Keeping the eye part or fully closed

• A bloodshot, angry-looking eye

• A cloudy patch appearing on the surface of the eye

• Rubbing at the eye

• Visible and red third eyelid at the inside corner of the eye

Herpes virus causes an ulcer which is narrow and branching, rather than a round crater. Vets call this a dendritic ulcer.

Cats most at risk of corneal ulcers

Although any cat can get an ulcer, especially due to trauma or infection, there are some breed, health and lifestyle factors that increase risk.

• Cats who go outdoors: more at risk of fight and thorn injuries

• Brachycephalic breeds: Persians, as their short faces and prominent eyes make the cornea vulnerable to injury and inflammation

• Cats who have dry eye

• Older cats whose cornea is less able to heal quickly or fully.

Complications of corneal ulcers in cats:

• Uveitis

• Corneal Sequestrum: part of the damaged cornea dies off and becomes hard and dark. The surrounding tissue sees this as a ‘foreign object’ and triggers inflammation. Which makes things worse.

• May look like a dark spot or piece of grit in the cornea

• Often mistaken for a foreign body

• May be pushed out of the eye eventually. But risks tracking deeper through the cornea and penetrating the eye.

How do vets diagnose corneal ulcers in cats?

Initial examination will confirm a painful inflamed eye. The vet will confirm the diagnosis with:

• Ophthalmoscope exam: checking the cornea and back of the eye with a light source and lens.

• Fluorescein dye test: applying a few drops of harmless dye to the eye. Dye clings to an ulcer but washes off the smooth healthy eye surface. The ulcer shows up as a green patch when the vet shines blue light on it.

• Slit lamp exam: a special instrument to examine the eye in detail. This can show the vet if any fluid is leaking out of the eye through a full-thickness ulcer.

How do vets treat corneal ulcers in cats?

As well as treating the ulcer, the vet will investigate and treat any underlying cause. Otherwise, recurrence is likely.

Treating uncomplicated ulcers

Eye drops or ointments:

• Antibiotic

• Lubricant or artificial tears

• Atropine: to increase the size of the pupil. Pain and inflammation cause the affected pupil to become tiny.

• Anti-inflammatory

• Antiviral for Feline Herpes virus

Medicine by mouth

• Non-steroidal anti-inflammatory pain relief

• Anti-viral treatment if needed

Most ulcers will heal within a week or so. For ulcers that fail to heal, vets may recommend a swab of the eye surface to check what bug is causing any infection present. If resistant to the previous treatment, a better option is selected.

For non-healing ulcers and sequestra

Operations under general anaesthetic:

• Superficial keratectomy: completely removing the top layer of the ulcer

• Graft: a healthy piece of tissue is used to repair a damaged one. For example, a piece of conjunctiva or healthy cornea.

Additional measures:

• A cone or buster collar: to prevent rubbing or scratching.

• Contact lens: the vet fits a sterile contact lens (just like a human one) to protect the healing eye.

Treating the underlying problems

• Removing a foreign body, like a thorn or splinter, from the eye

• Entropion surgery: an operation to correct in turned eyelids

• Removing extra or malpositioned lashes

• Treating dry eye with drops or surgery

Caring for a cat with a corneal ulcer at home

Corneal ulcers worsen very quickly, especially if they become infected. They need prescription eye drops from a vet to heal. However, recovery also depends on completing the treatment and protecting the eye from further trauma.

• Apply eye drops at the dose and frequency prescribed by your vet

• Seek help if you are struggling to put eye drops in

• Keep the cone collar on your cat at all times

• Bathe the eye with boiled, cooled water and a clean cotton pad once or twice daily or when discharge accumulates

• Ideally, keep indoors until healed

Reducing the risk of corneal ulcers in cats

Often, it’s an unfortunate chance that cats get eye ulcers. Particularly if it’s triggered by a piece of grit in the eye or conjunctivitis. However, some precautions can help reduce known risks.

• In neighbourhoods with many outdoor cats, it may be safer to keep yours’ indoors.

• Keep your cat's eyes clean: wipe away discharge to reduce the risk of conjunctivitis.

• Recognise what the discharge means and seek prompt veterinary advice to prevent corneal inflammation and ulcers.

  • Green or yellow discharge signals infection in the eye

  • Sticky discharge in the morning suggests a dry eye

When to worry about corneal ulcers in cats?

Call your nearest vet immediately if your cat:

• Appears suddenly blind

• Has a collapsed or sunken eyeball

• Has suffered a sharp penetrating eye injury (fence nail, glass, stick)

See a vet as soon as possible if your cat’s eye:

• Continues to look red and painful after treatment for conjunctivitis

• Has a cloudy patch visible on the eye or dark spot within the cornea

• Is painful, keeping the eye closed over

Joii can help with:

• Early recognition and treatment of conjunctivitis

• How to give and apply medicines

• Mild signs: sticky discharge, mildly inflamed eye

• Deciding if you need to see a vet in practice