Corneal ulcer in dogs (Ulcus corneae)

  • Occurrence: common
  • Location of disease: Head/Neck
Author: Dr. med. vet. Gisa Löwe | Last modified: 12.08.2026
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Definition

A corneal ulcer (Ulcus corneae) is a painful wound or erosion of the cornea of a dog’s eye that can be caused by injuries, infections, or other conditions. A deep corneal ulcer is always an emergency (Immediate/Emergency).

Das Wichtigste auf einen Blick

A corneal ulcer (Ulcus corneae) in dogs results from damage to the cornea, which protects the eye and focuses light. Causes are often physical traumas, infections, or dry eye (keratoconjunctivitis sicca). Certain breeds, such as bulldogs, are more susceptible due to their anatomy. Symptoms include increased blinking, redness, swelling, and eye discharge. Diagnosis requires an ophthalmic exam, often with a fluorescein test to make ulcers visible. If necessary, swabs or imaging procedures are used to identify infections and assess the extent of the damage.

Treatment depends on the cause and severity and includes antibiotic eye drops or ointments as well as anti-inflammatory medications. In severe cases or with infections, systemic antibiotic therapy may be necessary. Surgical interventions are possible for deep ulcers. The prognosis is good with early treatment, but untreated cases can lead to complications such as scar tissue formation or vision loss. Prevention includes regular eye examinations, keeping the eyes clean, and trimming facial hair in susceptible breeds. Good care and nutrition support the immune system and reduce the risk of infection. For chronic eye problems, regular eye drops or ointments are important.

Ursachen

The cornea is the transparent layer that covers the eye and plays a crucial role in protecting the inner structures as well as in focusing light. It consists of several layers, including the epithelium, Bowman’s membrane, the stroma, and Descemet’s membrane. A corneal ulcer occurs when these layers, particularly the epithelium, are damaged.

The causes of a corneal ulcer in dogs are varied. The most common include physical traumas caused by scratches, foreign bodies, or chemical influences. Infections by bacteria, viruses, or fungi can also lead to ulcers, especially if the dog’s immune system is weakened.

Another important factor is dryness of the eyes, also known as Keratoconjunctivitis sicca (KCS), which makes the cornea susceptible to ulcers. Dogs of certain breeds, such as bulldogs or Pekingese, have an increased risk of corneal ulcers due to their facial anatomy.

Symptoms

Rare symptoms:

Dogs with a corneal ulcer often show signs of discomfort and Pain in the affected eye. They may blink more frequently or squint (blepharospasm), and there may be increased tearing.

Another common symptom is conjunctival hyperemia (conjunctivitis) as well as a visible cloudiness or a milky spot on the cornea. In severe cases, pus formation and significant swelling of the eye may occur.

Behavioral changes such as irritability or loss of appetite may also occur, as the corneal ulcer is painful and impairs the dog’s well-being.

Diagnose

The diagnosis of a corneal ulcer requires a thorough ophthalmic examination by a veterinarian. An important diagnostic tool is the fluorescein test, where a special dye is applied to the cornea to make ulcers visible.

The veterinarian will also examine the entire eye structure to rule out possible causes such as foreign bodies or underlying infections. In some cases, a swab or culture may be taken to identify the type of infection, especially if standard treatment is not effective.

Imaging procedures such as ultrasound or special optical devices might be used to better assess the depth and extent of the ulcer and to ensure there are no further complications.

Therapie

Treatment for a corneal ulcer depends on the cause and severity of the condition. In most cases, therapy includes antibiotic eye drops or ointments to fight bacterial infections as well as anti-inflammatory medications to relieve Pain and Inflammatory conditions.

In severe cases, or if the ulcer is due to an infection that does not respond to topical treatments, systemic therapy with antibiotics may be necessary. For dry eyes, regular use of artificial tears or other moisturizing eye drops may be required.

Sometimes surgery is necessary, especially if the ulcer is deep or the cornea has been perforated by a foreign body or a severe infection. Techniques such as keratoplasty or conjunctival flap surgery can be used to repair the cornea and promote healing.

Prognose und Nachsorge

The prognosis for a corneal ulcer in dogs depends on the severity of the condition and the speed of treatment. In most cases, the prognosis is good if the ulcer is detected and treated early, and the cornea can heal without permanent damage.

However, in severe or long-untreated cases, there is a risk of complications such as scar tissue formation, which can lead to visual disturbances, or in extreme cases, loss of the eye. Regular follow-up care is crucial to monitor the healing process and minimize the risk of recurrence.

Prävention

The prevention of corneal ulcers in dogs involves several approaches. Regular eye exams, especially for breeds prone to eye problems, can help detect and treat these early.

It is important to keep the dog’s eyes clean and free of foreign objects. In dogs with protruding eyes or long hair on their face, trimming the fur around the eyes can help prevent irritation and injury.

Good general care and nutrition support the dog’s immune system and can help prevent infections that lead to a corneal ulcer. For dogs suffering from KCS or other chronic eye problems, regular and consistent use of prescribed eye drops or ointments is essential.

Ausblick auf aktuelle Forschung

The Ulcus corneae in dogs is a defect of the cornea that can range from a superficial erosion to a deep ulcer at risk of perforation. Clinically, it is important that not every corneal ulcer is biologically the same: infectious, “melting,” traumatic, or poorly healing ulcers differ significantly in terms of risk and therapy. Brachycephalic dogs, in particular, have an increased risk because the palpebral fissure, tear film, and corneal exposure often interact unfavorably. (merckvetmanual.com, pubmed.ncbi.nlm.nih.gov)

The most important research outlook today lies in earlier risk assessment and more precise classification. The goal is to identify more quickly which ulcers heal with conservative treatment and which rapidly progress towards keratomalacia or perforation. In this context, more precise ophthalmological classifications, microbiological diagnosis, and the evaluation of tear film, eyelid function, and corneal innervation are gaining importance. (merckvetmanual.com, pubmed.ncbi.nlm.nih.gov)

Therapeutically, the outlook is particularly dynamic. Corneal cross-linking, biological and bioengineered grafts, serum-based therapies, and other regenerative approaches are being investigated to better control infection, tissue degradation, and scar tissue formation. (pubmed.ncbi.nlm.nih.gov, pubmed.ncbi.nlm.nih.gov)

Overall, research is clearly moving away from the blanket term “corneal ulcer” towards cause- and risk-adapted corneal medicine, with the aim of more reliably preserving vision and the globe.

Frequently Asked Questions (FAQs)

1. What is a corneal ulcer?
A corneal ulcer is a corneal ulcer, meaning a substance defect of the cornea. Depending on the depth, superficial, deeper stromal, and descemetocele ulcers up to corneal perforations are distinguished. Corneal ulcers are painful and can lead to permanent damage or eye loss if delayed.
2. What are the causes?
Common causes include traumas (claw injuries, foreign bodies), eyelid malpositions such as entropion, faulty eyelid closure in brachycephalic breeds, dry eye (Keratoconjunctivitis sicca), bacterial and viral infections, chemical irritations, or distichia. Chronic eye diseases also promote their development.
3. What Symptoms occur?
Typical signs are squinting, tearing, reddened conjunctiva, light sensitivity, rubbing with the paw, corneal clouding, and occasionally purulent eye discharge. Deep ulcers often show a significant indentation of the cornea, sometimes with protrusion of Descemet's membrane.
4. How is the diagnosis made?
The diagnosis is made by ophthalmological examination with a slit lamp and fluorescein staining of the cornea. The dye adheres to defective areas and makes the ulcer visible. Additionally, tear production (Schirmer test), intraocular pressure, and, if necessary, bacteriological swabs are examined.
5. How is a corneal ulcer treated?
Superficial ulcers are treated with topical antibiotics and analgesic eye drops (atropine, tear substitutes if necessary). Healing usually occurs within 5 to 10 days. For deep or chronic ulcers, surgical measures such as conjunctival flap, corneal transplantation, or tarsorrhaphy are required.
6. What is an indolent ulcer?
Indolent ulcers are superficial ulcers that do not heal because the epithelial cells do not adhere to the underlying stroma. They occur primarily in Boxers, Poodles, and older dogs. Treatment requires mechanical debridement (cotton swab) and, if necessary, corneal scarification (Grid Keratotomy or diamond burr).
7. When is surgery necessary?
Surgery is necessary for deep, melting, perforated, or non-healing ulcers. Standard procedures include the conjunctival flap, pedicle flap, or corneal transplants. These interventions stabilize the cornea and create the conditions for healing.
8. What role do brachycephalic breeds play?
Pugs, French Bulldogs, and similar brachycephalic breeds have a significantly increased risk of corneal ulcers due to protruding eyes, incomplete eyelid closure, and reduced corneal protection. Even small injuries can rapidly develop into severe defects. Adapted Prevention is important.
9. Which pain therapy is useful?
Corneal ulcers are very painful. Atropine eye drops relax the ciliary muscle spasm and reduce Pain; systemic non-steroidal anti-inflammatory agents are additionally helpful. Topical local anesthetics are used only diagnostically, as they delay corneal healing.
10. What is the prognosis?
With timely and professional treatment, most superficial ulcers heal without permanent visual impairment. Deep or perforated ulcers often lead to Scar tissue formation and pigment deposits, which can limit vision. A corneal perforation is an emergency and can, in rare cases, mean eye loss.

Literatur

  • O’Neill, D. G., Lee, M. M., Brodbelt, D. C., Church, D. B., & Sanchez, R. F. (2017). Corneal ulcerative disease in dogs under primary veterinary care in England: Epidemiology and clinical management. Canine Genetics and Epidemiology, 4, Article 5. https://doi.org/10.1186/s40575-017-0045-5
  • Ledbetter, E. C., & Gilger, B. C. (2013). Diseases and surgery of the canine cornea and sclera. In K. N. Gelatt, B. C. Gilger, & T. J. Kern (Eds.), Veterinary ophthalmology (5th ed., pp. 976–1049). Wiley-Blackwell.
  • Bentley, E. (2005). Spontaneous chronic corneal epithelial defects in dogs: A review. Journal of the American Animal Hospital Association, 41(3), 158–165. https://doi.org/10.5326/0410158
  • Gosling, A. A., Labelle, A. L., & Breaux, C. B. (2013). Management of spontaneous chronic corneal epithelial defects (SCCEDs) in dogs with diamond burr debridement and placement of a bandage contact lens. Veterinary Ophthalmology, 16(2), 83–88. https://doi.org/10.1111/j.1463-5224.2012.01026.x
  • Tsvetanova, A., Powell, R. M., Tsvetanov, K. A., & Gould, D. J. (2021). Melting corneal ulcers (keratomalacia) in dogs: A 5-year clinical and microbiological study (2014–2018). Veterinary Ophthalmology, 24(3), 265–278. https://doi.org/10.1111/vop.12885
  • Kowalska, M. E., Shukla, A. K., Arteaga, K., & Pot, S. A. (2023). Evaluation of risk factors for treatment failure in canine patients undergoing photoactivated chromophore for keratitis–corneal cross-linking (PACK-CXL): A retrospective study using additive Bayesian network analysis. BMC Veterinary Research, 19, Article 224. https://doi.org/10.1186/s12917-023-03776-0
  • James-Jenks, E. M., Pinard, C. L., Monteith, G., & Sebbag, L. (2023). Evaluation of corneal ulcer type, skull conformation, and other risk factors in dogs: A retrospective study of 347 cases. Canadian Veterinary Journal, 64(3), 225–234.