Dog Eye Ulcer: Symptoms, Causes, and What to Do Right Away

Last updated: August 21, 2026 · By the Dog Health Insider Editorial Team

Table of contents

• What a corneal ulcer actually is
• Symptoms of a dog eye ulcer
• Causes and high-risk breeds
• How vets diagnose it (fluorescein stain)
• Veterinary treatment options
• Safe at-home support (and what to never do)
• Ulcer vs other common eye problems
• Healing timeline and aftercare
• FAQ

What a dog eye ulcer actually is

The cornea is the transparent dome at the front of the eye. It is only about half a millimetre thick in most dogs and is built in layers: the outer epithelium, the thick supportive stroma, then Descemet membrane and the inner endothelium. When the epithelium is scraped away, the exposed stroma is called a corneal ulcer or ulcerative keratitis.

Depth is what decides urgency. A superficial corneal abrasion involves only the epithelium and often re-covers itself in three to five days with medication. A stromal ulcer digs into the middle layer. A descemetocele has eroded all the way down to Descemet membrane — a single transparent layer holding the eye together, which can rupture. Only a veterinarian can tell these apart, and the outward appearance of a mild and a severe ulcer can look almost identical to an owner.

Symptoms of a dog eye ulcer

Corneal nerve density is extremely high, so ulcers hurt. Watch for:

• Sudden squinting (blepharospasm) or holding one eye shut
• Excessive watery tearing, sometimes turning to green-yellow discharge if bacteria take hold
• A cloudy, hazy or bluish spot on the surface — corneal oedema, fluid moving into the injured tissue
• Red, inflamed conjunctiva and visible blood vessels creeping in from the edge of the cornea
• Light sensitivity (photophobia) and reluctance to go outside
• Rubbing the face on carpet or pawing at the eye
• A dull, roughened or dented look to the eye surface in side lighting
• Lethargy, reduced appetite or a head-shy reaction to being touched near the head

Rubbing makes everything worse. If your dog is pawing at the eye, get a cone (Elizabethan collar) on before the drive to the clinic.

Causes and high-risk breeds

Higher-risk breeds: Pugs, French and English Bulldogs, Shih Tzus, Boston Terriers, Pekingese and Boxers because of exposed corneas and reduced corneal sensitivity; plus any breed prone to dry eye, such as the Cocker Spaniel, West Highland White Terrier and Cavalier King Charles Spaniel.

How vets diagnose it

The core test is a fluorescein stain. An orange dye is dropped on the eye; it will not stick to intact epithelium but binds to exposed stroma, so the ulcer glows bright green under blue light. Your vet will typically also perform a Schirmer tear test before staining (to rule out dry eye), measure intraocular pressure to rule out glaucoma, examine under the third eyelid for foreign material, and in stubborn cases take a corneal cytology or culture. Deep, melting or non-healing ulcers are commonly referred to a board-certified veterinary ophthalmologist (ACVO diplomate).

Veterinary treatment options

Treatment is always prescription-based. Depending on depth, your veterinarian may use topical broad-spectrum antibiotic drops or ointment, atropine for painful ciliary spasm, oral anti-inflammatory pain relief, and in melting ulcers anti-collagenase therapy such as autologous serum. Non-healing superficial ulcers (SCCEDs, the classic Boxer ulcer) often need a debridement procedure such as a diamond burr or grid keratotomy. Deep ulcers and descemetoceles may require surgery — a conjunctival graft or corneal transplant.

Safe at-home support

Home care supports professional treatment, it never replaces it. Once your veterinarian has examined the eye:

1. Keep the cone on for the entire treatment period, including overnight.
2. Give every prescribed dose on time. Frequency matters more than volume with topical eye medication.
3. Wipe discharge away from the eye with a clean, damp cotton pad, moving outward, using a fresh pad per eye.
4. Avoid dusty environments, long car rides with the window down, and swimming until healing is confirmed.
5. Recheck as scheduled. A repeat fluorescein stain is the only way to know the ulcer has closed.

For long-term maintenance in dogs prone to irritation — flat-faced breeds, seasonal allergy sufferers, dogs with chronic tear staining — a gentle sterile rinse used on healthy eyes helps clear pollen, dust and dried discharge before it accumulates. Read our wider guide to dog eye care and our breakdown of dog eye discharge for what normal versus abnormal looks like.

Ulcer vs other common eye problems

Because a painful cloudy eye can be an ulcer or glaucoma, and the treatments are opposite, self-diagnosis is not safe.

Healing timeline and aftercare

Some scarring or a faint haze can persist and usually does not affect vision meaningfully. Dogs with a structural cause — entropion, distichiasis, dry eye — will keep re-ulcerating until that cause is corrected.

Frequently asked questions

Will a dog eye ulcer heal on its own?

A very small abrasion sometimes re-epithelialises, but there is no safe way for an owner to judge depth at home. Untreated ulcers can become infected and deepen quickly, so all suspected ulcers need veterinary assessment.

How much does treatment cost?

In the United States, a straightforward exam with fluorescein stain and antibiotic drops commonly runs roughly 150 to 400 US dollars. Deep or melting ulcers requiring ophthalmology referral and surgery can reach several thousand dollars, which is why same-day care is also the cheaper path.

Can I use human artificial tears or saline?

Plain sterile saline can be used to flush obvious debris on the way to the clinic. Medicated human drops, redness relievers and any product containing a steroid should never be used on a dog eye without veterinary direction.

Is a corneal ulcer contagious to my other dogs?

The ulcer itself is not. If it was triggered by an infectious conjunctivitis, that underlying infection can sometimes spread, so keep shared bedding and towels separate until your vet advises otherwise.

Why does my flat-faced dog keep getting them?

Brachycephalic dogs have prominent eyes, shallow orbits, sometimes incomplete blinking and reduced corneal sensitivity, so minor trauma goes unnoticed and dries out. Preventive daily eye checks and correcting eyelid abnormalities make the biggest difference.

Can supplements help an ulcer?

No supplement supports the closure of an active corneal ulcer, and no wellness product should be presented that way. Supplements and rinses belong to routine maintenance of a healthy eye, not to the management of an injury.

When to call the vet immediately

Go now if you see a hard-shut eye, a visibly cloudy or blue eye, a bulging or enlarged eye, blood in the eye, a foreign object you can see, sudden apparent blindness, or any eye change in a flat-faced breed. Vision loss from a perforated cornea is often permanent.

Sources

• Merck Veterinary Manual — Eye Diseases and Disorders: ulcerative keratitis in animals.
• American Kennel Club, Expert Advice: Health — corneal ulcers and eye injuries in dogs.
• American College of Veterinary Ophthalmologists (ACVO) — owner resources on corneal disease and referral criteria.
• American Veterinary Medical Association (AVMA) — guidance on recognising veterinary emergencies.

Related reading

• The complete guide to dog eye care
• Dog eye infections: signs and next steps
• Dog eye discharge explained
• Dog pink eye (conjunctivitis)

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