Infectious keratitis and corneal ulcers refer to the inflammation or irritation of the cornea that occurs due to invasion of an infectious organism, such as virus (herpes simplex virus type 1, reactivation of chicken pox virus, adenoviruses etc.), bacteria, parasite etc. into the cornea.

Corneal ulcer occurs when eye’s natural resistance to infection is bargained due to eye trauma or excessive use of contact lens giving target area to the infection. Infection of eye is the major cause of microbial keratitis and this has tremendously increased following the introduction of soft lenses.

The causative agents of infective keratitis may include the following:

  1. Bacteria: Gram-positive cocci and Gram-negative bacilli
  2. Fungi: Filamentous fungi
  3. Viral: Herpes simplex virus
  4. Parasite: Acanthamoeba species

Risk factors of Infectious Keratitis/ Corneal Ulcers

Some of the common risk factors that can predispose a person to infectious keratitis include the following:

  • Severe dry eyes
  • Eyelid disease
  • Trauma from a foreign body (including contact lenses)
  • Overuse of contact lens
  • Poor hygiene of contact lens
  • Re-use of contact lens solution
  • Sleeping in contact lenses

Causes of Infectious Keratitis/ Corneal Ulcers

Infectious Keratitis or Corneal Ulcers occurs due to entry of bacteria, fungus, or parasites into the cornea because of any of the following:

  • Complication of wearing contact lens
  • Corneal trauma
  • An irregular ocular surface
  • Vitamin A deficiency


The severity of symptoms caused by infectious keratitis depends upon the depth of the corneal infection and causative organism of the infection. Some of the peculiar symptoms include:

  • Pain and eye irritation
  • Eye redness
  • Foreign body sensation especially on eye blinking
  • Blurred vision
  • Light sensitivity
  • Purulent discharge
  • Watery eyes
  • Vision loss due to corneal scarring


A corneal infection can be diagnosed on eye examination by an eye care professional. But more severe samples need corneal culture or biopsy examination to identify the offending organism or confirm the diagnosis. Confocal microscopy may be used in the differential diagnosis of infectious keratitis.


Infectious keratitis should always be treated as an ocular emergency due to its rapid progression and disastrous complications. Its management should be done with any of the following according to the condition of the patient:

  • Empirical anti-bacterial or antibiotic eye drops to eliminate the infection
  • Steroid eye drops to reduce inflammation
  • Collagen crosslinking (CXL) with riboflavin and ultraviolet-light A
  • Corneal transplantation

Complications of Infectious keratitis:

Chronic or untreated Infectious keratitis may result in following complications:

  • Perforation
  • Endophthalmitis
  • Corneal ulceration
  • Blindness