Felis ISSN 2398-2950

Cornea: ulcerative keratitis

Contributor(s): Dennis E Brooks, Peter Renwick, David Williams, Natasha Mitchell


  • Important ocular disease characterized by loss of corneal epithelium plus variable amounts of stroma.
  • Cause: complex; trauma, collagenase activity and bacterial/viral infections should be considered.
  • Mycotic infection is more common in dogs than cats in the USA.
  • Signs: ocular discharge, red eye, corneal ulceration, painful eye.
  • Diagnosis: relatively straightforward; use of fluorescein dye and ultraviolet/cobalt blue light is strongly advised.
  • Treatment: remove causative agent(s) and create an environment suitable for healing.
  • Prognosis: corneal rupture is a possibility in cases of deep ulceration. Recurrence is likely if the underlying cause is not identified and treated.



  • Trauma: blunt, penetrating or perforating.
  • Collagenases.
  • Bacteria.
  • Viruses - FHV-1 ulceration common.
  • Adnexal abnormalities, eg exposure keratitis, entropion, eyelid mass rubbing, eyelid agenesis Eyelid: abnormality.
  • Corneal necrosis (corneal sequestrum) Cornea: sequestration.

Predisposing factors


  • Brachycephalic breeds. Lagophthalmos, poor distribution of the tear film, entropion at the medial aspect of the lower eyelids, and globe exposure making trauma more likely are all factors involved.



  • Rapid progression of superficial ulcers to corneal rupture, may occur as a result of collagenase activity. Liquefactive corneal necrosis, or corneal 'melting' is a very serious potential complication of all forms of corneal ulceration.
  • Indolent ulcers are non-healing epithelial erosions which do not penetrate the corneal stroma. FHV-1 may be the cause.
  • Same as keratitis Keratitis.
  • Initial corneal injury  →  allows bacteria to adhere to ocular surface.
  • Melting ulcers occur following liberation of collagenase enzymes from invading microorganisms, white blood cells or keratocytes, which cause rapidly collagenolysis and loss of corneal structure.
  • If stroma overlying Descemet's membrane is absent  →  descemetocele (the exposed membrane then may bulge forwards as a result of intra-ocular pressure).
    Descemetoceles do not stain with fluorescein dye at the base, but the edges of the ulcer are fluorescein positive.
  • FHV-1 keratitis is epithelial unless topical steroid causes immunosuppression leading to stromal keratitis.
  • Corneal sequestrum occurs as a result of stromal collagen necrosis.


  • Melting ulcers can progress over a matter of hours.
  • Superficial ulcers can be chronic and present for several weeks.
  • Ulcers that become corneal sequestra can be present for many months to years.


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Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • La Croix N C, van der Woerdt A & Olivero D K (2001) Nonhealing corneal ulcers in cats - 29 cases (1991-1999)​. JAVMA 218 (5), 733-735 PubMed.
  • Featherstone H & Sansom J (2000) Intestinal submucosa repair in two cases of feline ulcerative keratitis. Vet Rec 146 (5), 136-138 PubMed.
  • Kern T J (1990) Ulcerative keratitis. Vet Clin North Am Small Anim Pract 20 (3), 643-666 PubMed.

Other sources of information

  • Petersen-Jones S & Crispin S (2002) BSAVA Manual of Small Animal Ophthalmology. 2nd edn. British Small Animal Veterinary Association. ISBN 0 905214 54 4