Home › Animalia › Animal health › Animal diseases › Corneal ulcer in dogs
Corneal ulcer in dogs
The cornea is the transparent window at the front of the eye. An ulcer is a loss of substance of this window: the superficial layer is torn off and the deeper layers are exposed. It is a very painful lesion, comparable to an abrasion on an...
What is it?
The cornea is the transparent window at the front of the eye. An ulcer is a loss of substance of this window: the superficial layer is torn off and the deeper layers are exposed.
It is a very painful lesion, comparable to an abrasion on an area extremely rich in nerve endings.
A superficial ulcer can heal in a few days. A deep ulcer can deepen to perforate the eye in a short time. It is for this reason that an eye that remains closed must always be seen quickly.
Key point
A corneal ulcer can progress very quickly. A painful eye that remains closed should never wait until the next day, and no eye drops should be applied without veterinary advice.
Commonly observed signs
These signs are neither exhaustive nor specific. Only a veterinarian can establish a diagnosis.
Related signs — each one links to its page:
Eye kept closed or half-closed, incessant blinking.
Sharp pain: the dog steps back when the hand is brought close to its head, rubs against the rugs or with the paw.
Marked redness of the white of the eye and profuse tearing, first clear then thick if an infection is present.
Blue or whitish veil on the cornea, sometimes a small crater visible in raking light.
Pupil often narrowed on painful side.
Dejection, refusal to play, sensitivity to bright light.
When to consult without delay
This list does not replace veterinary advice. It gathers situations that justify a prompt consultation.
Causes and risk factors
Direct trauma: scratch from a cat, branch, spikelet, sharp grass, thrown dust, shampoo or household product received in the eye.
Lack of tears: a dry eye ulcerates easily and heals poorly.
An abnormality of the eyelids or eyelashes that continually rub against the cornea, as in entropion.
Added infection: bacteria or fungi that colonize an already present wound and quickly widen it.
Facial paralysis or a very protruding eye that does not close completely, leaving the cornea to dry out.
Breeds with flattened faces and bulging eyes are the most exposed: their eyelids do not cover the eye well and the slightest shock reaches the cornea.
Dogs prone to dry eye or carriers of entropion.
Hunting dogs and those who run in brush, exposed to spikelets and branches.
A previous episode of ulcer in the same eye, particularly when healing had been long.
Diagnosis and care
Diagnosis is the veterinarian's responsibility, based on clinical examination and laboratory tests. Care is decided case by case.
The veterinarian applies a green dye to the eye: it attaches only where the cornea is raw and makes the ulcer visible, with its exact contours.
He assesses the depth of the lesion, looks for a foreign body under the eyelids and turns the third eyelid over to inspect it.
It measures tear production and examines the position of the eyelids and eyelashes, because a recurring ulcer almost always has an underlying cause.
A sample for bacterial analysis is sometimes taken from deep or non-healing ulcers.
A close check, often every few days, makes it possible to check that the ulcer is closing instead of widening.
Treatment
The treatment combines antibiotic eye drops to avoid or control the infection, and treatment of pain, which is real and often underestimated.
Eye drops that dilate the pupil are sometimes prescribed to calm the painful spasm inside the eye.
The collar is not an optional accessory: a dog rubbing itself can transform a superficial ulcer into a surgical emergency in just a few seconds.
Never put eye drops prescribed for something else into the eye, and especially not eye drops containing corticosteroids: on an ulcer, it delays healing and can lead to perforation.
Deep, sunken or perforated ulcers require surgery; the veterinarian can cover the weakened area with a tissue graft to save the eye.
The underlying cause must be treated in parallel, otherwise the ulcer returns.
Treatment depends on the cause and the animal's condition: it must be determined by a veterinarian. No self-medication.
Prevention
Rinse the eye with physiological saline after an outing in dense vegetation if you see the dog blinking with one eye.
Protect the dog's head in a vehicle: do not let him take it out of the window, dust and insects thrown at this speed will injure the cornea.
Have any persistent tearing on one side checked rather than waiting.
In breeds with protruding eyes, have tear production and eyelid position checked during routine visits.
Possible complications
Deepening of the ulcer to the inner layers, then perforation of the eye.
Severe infection which liquefies the cornea in a few dozen hours: the eye takes on a melted, gelatinous appearance.
Permanent opaque scar on the axis of vision, which hinders vision.
In the most serious cases, loss of the eye despite treatment.
When to see a veterinarian
Your dog keeps one eye closed: this is already reason for consultation the same day.
The eye is red, watering a lot and the dog refuses to have his head touched.
A white, bluish veil or a small hollow appears on the surface of the eye.
Something got in the eye, although the dog seemed to get better afterward.
The eye seems deformed, protruding, or you see fluid leaking from a wound in the cornea: immediate emergency, do not put anything in the eye and go to the veterinarian.
Prognosis
A superficial ulcer caught early generally heals within a few days without visible after-effects.
A deep ulcer requires intensive treatment and sometimes surgery; the eye can be saved, often at the cost of a scar.
Ulcers that persist without an identified cause should be investigated for a dry eye, eyelid defect or hidden foreign body.
The processing time is the factor that changes the result the most.
Frequently asked questions
My dog hit his eye but he reopens it: should I consult?
Yes. An ulcer may be present as the dog reopens the eye at times. Only the dye test allows this to be seen, and a lesion caught early is treated much more simply.
Can I use eye drops I have at home?
No. Many human eye drops or old prescriptions contain corticosteroids, which aggravate an ulcer and can lead to perforation. Only rinsing physiological serum is risk-free.
Is the collar essential?
Yes, day and night for the entire duration of treatment. A single scratch can ruin several days of healing and transform a benign lesion into a surgical emergency.
Will my dog keep track?
Superficial ulcers often heal without marks. Deep ulcers frequently leave a whitish scar, only annoying if it is in the center of the visual axis.
References
WSAVA — World Small Animal Veterinary Association
Content reviewed by the TunisieVet editorial team · Updated 09 August 2026
AT A GLANCE
Need a veterinarian?
Find a practitioner near you on TunisieVet, with their specialities, hours and contact details.
Find a veterinarianCategories
Affected species
This information is provided for educational purposes only and is not a substitute for a veterinary consultation. If you have any concerns about your animal's health, consult a veterinarian.
To discover
Related diseases and linked Animalia content.
Canine parvovirus
Viral · Vaccine available
Canine distemper
Viral · Vaccine available
Kennel cough
Viral · Vaccine available
Canine leishmaniasis
Parasitic