Corneal Ulcers in Pets: Diagnosis & Treatment
A corneal ulcer is a painful open sore on the clear surface of the eye. Quick veterinary treatment is essential to prevent permanent damage.
The cornea is the transparent dome-shaped surface that covers the front of the eye. When this protective layer is damaged — whether by trauma, infection, or underlying disease — it creates an ulcer that can cause significant pain and threaten vision.
Key Points
- Corneal ulcers are one of the most common causes of eye pain in pets
- Causes include trauma, foreign bodies, dry eye, and viral infections
- Shallow ulcers heal within days with medication; deep ulcers may need surgery
- Brachycephalic breeds (flat-faced dogs and cats) are at higher risk
- Never use human eye drops on pets without veterinary guidance
- Deep or melting ulcers are emergencies requiring immediate surgery
What Causes Corneal Ulcers?
Trauma is the leading cause — scratches from cats, plant material, or rubbing the eye. Chemical irritation from shampoos or cleaners can also damage the cornea. Dry eye (keratoconjunctivitis sicca) prevents proper lubrication. In cats, feline herpesvirus is a major cause of recurrent ulcers. Some breeds like Pugs, Persians, and Bulldogs have prominent eyes that are easily injured.
Signs Your Pet Has an Ulcer
Pets with corneal ulcers show intense pain. You'll see squinting, excessive tearing, redness, and the pet may paw at the affected eye. The eye may appear cloudy or have a visible divot on the surface. Some pets become withdrawn or refuse to eat due to pain. Light sensitivity is common. In severe cases, the eye may bulge or rupture.
Diagnosis at the Vet
Your veterinarian uses fluorescein stain — a harmless orange dye that turns green when it contacts damaged corneal tissue — to visualize the ulcer. A Woods lamp or slit-lamp exam assesses depth and size. Tear production testing (Schirmer test) identifies dry eye. Cultures may be taken for infected ulcers. Ultrasound or CT helps if there's associated eye trauma.
Treatment & Recovery
Superficial ulcers heal with antibiotic eye drops and an e-collar to prevent rubbing. Pain medication is essential. Deeper ulcers may require debridement or a grid keratotomy to encourage healing. Very deep or melting ulcers need surgical grafting with conjunctival tissue or a biosynthetic graft. Healing typically takes 1-2 weeks for simple ulcers; complex cases may take a month.
When to See a Vet Immediately
- Your pet is squinting or holding an eye closed
- There's visible cloudiness or a divot on the eye surface
- The eye is red with excessive tearing
- Your pet is pawing at their face
- The third eyelid is raised
How RVC Can Help
This article is for educational purposes only and does not replace professional veterinary advice. If your pet is showing any symptoms, please contact Royal Veterinary Center immediately at +853 6677 6611.