Corneal Ulcer

See also Keratitis

Corneal ulcers are included due to their relatively common presentation in practice. Incidence reports vary, however up to 4 in 10,000 people are reported to have experienced a corneal ulcer. They are much more common in the contact lens wearing population. 

Corneal ulcers are a serious, potentially sight threatening, ocular emergency and it is important that DOs recognize the possible presentation in practice and are able to take appropriate action to ensure prompt referral. 

A corneal ulcer is a form of keratitis, often described in the literature as “an open sore or erosion on the cornea epithelium”. Corneal ulcers often involve the deeper stromal layers and occasionally lead to corneal perforation.  

Ulcers start as a keratitis (inflamed cornea) usually after damage to the protective corneal epithelium allows bacteria to enter. There is a range of causes of the epithelial damage but in practice it is usually following corneal abrasions, contact lens misuse or some other ocular injury. 

Usually unilateral in cases caused by injury or infection, corneal ulcers can be bilateral if due to causes such as chronic dry eye, vitamin A deficiency, Sjogren’s syndrome or rheumatoid arthritis. 


  • Pain 
  • Photophobia 
  • Foreign body sensation 
  • Lacrimation 
  • Red eye 
  • Reduced vision 
  • Nausea in severe cases 
  • Miosis (reduced pupil aperture) 
  • Visible “white” opacity – hard to spot but visible on slit lamp after staining with fluorescein (see image below) 


  • Ulcers are the by-products of corneal trauma which has allowed a chance infection to take hold. This may be physical trauma to the cornea, mechanical insult, chemical injury, injury by vegetation etc. 
  • Misuse of contact lenses – poor cleaning, overwear etc, can cause both mechanical insult to cornea and be a transmission vehicle for infection. 
  • Bacterial Infections- Staphylococcus aureus, Pseudomonas aeruginosa, Staphylococcus fusarium are common bacteria associated with ulcers. 
  • Viral Infections– herpes simplex, varicella virus, herpes zoster and others. 
  • Fungal Infections  aspergillosis, candidiasis, candida auris. Usually the transmission route is vegetive- injuries to eyes following gardening, agricultural work etc. 
  • Parasitic infections- Acanthamoeba, an amoeba found in tap and bottled water, seawater, rivers, lakes, chlorinated pools and spas, soil & dust. 

This patient presented with a sore, red eye and foreign body sensation. Patient was a regular soft contact lens wearer. Note in this photo a very faint corneal opacity as indicated by the arrow which would be difficult to spot with a naked eye.  

Same patient now with a corneal section illuminated on a slit lamp. The position of the corneal ulcer is clearly visible. If there is epithelial loss then the use of fluorescein would help identify and distinguish the site of the ulcer.

Site of an ulcer clearly visible to the naked eye.  

Fungal keratitis ulcer – opacity can clearly be seen across whole of the cornea with a naked eye. Fungal ulcers are less common but much more difficult to identify and treat.

Large ulcer – note general corneal haze and hypopyon.  

Classic dendritic ulcer caused by herpes simplex virus – note branch like appearance.  


  • Will depend on identification of causative agent: 
      1. Antibiotic treatment  chloramphenicol 
      2. Antiviral treatment  acyclovir 
      3. Antifungal treatment – Natamycin 
  • Analgesics for pain 
  • Steroid eye drops to reduce inflammation (after initial treatment for causative agent) 
  • Vitamin C treatments to reduce chance of scarring 

Red Flags: 

For corneal ulcers the presenting symptoms are the red flags however certain conditions are more likely to be associated with corneal ulcers and may help in diagnosis 

  • Diabetes 
  • Recent ocular surgery 
  • Horticultural or agricultural work (higher risk of fungal infections) 
  • Use of topical ocular corticosteroids 
  • Vitamin A deficiency 
  • Blepharitis  
  • Entropion 
  • Severe allergic disease 
  • Recent history of cold sores, chicken pox, herpes, shingles 

When one or more of these red flags is raised, a conversation with another registrant in practice should take place following which appropriate referral or management should be actioned and noted. If there are no other registrants in practice then contact should be made with colleagues elsewhere or contact should be made for advice to the local Hospital Eye Service (HES).