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Corneal ulcers are often incredibly uncomfortable and painful for pets, so it’s important to know what to look out for. This handy guide will take you through everything you need to know about corneal ulcers, from causes and symptoms, through to treatment.

What is a Corneal Ulcer?

Corneal ulcers occur when the surface layer of the clear cornea has been damaged, exposing the deeper tissues (including nerves). These can range from being fairly shallow, such as minor grazes and scratches, to much deeper, more serious ulcers known as a Deep Corneal Ulcer or stromal ulcer.

Corneal ulcers can be very painful for your pet and can quickly become more serious if bacteria (or sometimes fungus) penetrate deeper into the eye causing infection. The front of your pet’s eye is very thin and can easily burst as the result of deep corneal ulcers in particular.

Deep Corneal Ulceration

A Deep corneal ulcer is an eye ulcer that extends further into the corneal stroma (the thickest layer of the cornea). Usually, if an ulcer extends past half of the corneal thickness, surgery will be required to fix the problem.

Causes of Corneal Ulcers In Pets

The most common cause of corneal ulcers in pets is trauma. This could be something as minor as your pet rubbing their eye on something, contact with a sharp object (like a cat claw or a thorn) or just a simple scratch. Another cause of corneal ulcers is chemical burns from shampoo or other household products.

Other causes include:

What are the Symptoms of Corneal Ulcers?

Your pet’s cornea is one of the most sensitive parts of their body. As such, you often notice a significant amount of discomfort if they have a corneal ulcer. Common symptoms of corneal ulcers include:

Increased Blinking and Squinting

Corneal ulcers are usually uncomfortable and painful. As such, your pet may blink more than usual or you may find them squinting, or even completely closing their eyes.


Due to the irritation you will likely see an increase in ocular discharge ranging in colour from clear, white, yellow or green.

Red, Bloodshot, or Cloudy Eyes

Your pet’s eye may appear red and bloodshot, and in some cases may be swollen. Your pet’s cornea may also appear hazy or cloudy.

Increased Scratching and Rubbing Around the Eye

You may find that with a corneal ulcer, your pet will excessively scratch or rub their eyes due to discomfort. It is important to pick up on this in particular as rubbing at the eyes may make the condition worse.

An Obvious Crater in the Eye

With larger ulcers you may be able to spot a crater or depression in the surface of the eye.

Avoiding Bright Lights

Your pet’s eyes are incredibly sensitive at the best of times. With a corneal ulcer, you might find that bright lights cause an irregular level of pain and discomfort.

What is the Treatment for Corneal Ulcers?

Treatment for corneal ulcers will depend on the severity of your pet’s ulcer. These may include:

An Elizabethan Collar

This will prevent your pet from rubbing or scratching their eyes whilst they heal. It’s essential for the treatment of eye ulcers.

Eye Drops

You may be given one or more eye drop medications to help with the treatment of corneal ulcers. These may be antibiotic drops to prevent or treat infections, lubricating drops to soothe the eye and keep it moist, atropine drops may be given if your pet has developed a small pupil, serum eye drops may be given to help prevent ulcers getting deeper, and anti-inflammatory drops may be advised to help reduce knock-on effects such as uveitis.

Anti-Inflammatory Pain Relief

Corneal ulcers can cause a great deal of discomfort and pain for your pet. Your vet may prescribe painkillers to help.

Oral Antibiotics

These aren’t always necessary, however may be prescribed if there is concern for your pet developing an infection. Certain antibiotics have special healing properties when it comes to corneal ulcers. Speak to us for more information.

Corneal Crosslinking (CXL)

In cases where ulcers are situated at less than 50% depth, Corneal Crosslinking may be a viable treatment option. Vets will serially administer Vitamin B2 eye drops to the surface of the eye, which is then activated by ultraviolet (UV) light to make the tissues in the cornea stronger. CXL has the added advantage that it sterilises the ulcerated site. This treatment offers a safe alternative to more invasive methods.


If your pet’s eye has been damaged badly, particularly if they have a deep corneal ulcer, surgery may be required to prevent or treat rupture. This will be performed under general anaesthesia, using an operating microscope with the aim of supporting the weakened cornea. A graft will be stitched into the deficit and if the cornea is infected, your surgeon may recommend crosslinking to kill any bacteria present.

By attending Knutsford Vets Surgery, your pet will be in the safe hands of experienced Ophthalmologist, Dr Paul Adams. Dr Adams has years of experience treating a wide range of pet eye conditions, and is the perfect partner to look after your pet’s ocular health.

Our friendly team is on hand if you have any questions. Contact us on 01565 337999.

Knutsford Vets Surgery

It’s always best to consult your vet if you think that your pet has an issue with their eyes, however it is vitally important to do so if they show signs of a corneal ulcer. Not only does this cause a great deal of discomfort, but can also result in severe damage if left untreated.

Call Knutsford Vets Surgery immediately if you spot these signs on 01565 337999.

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