keratitis

Last reviewed 01/2018

Keratitis is inflammation of the cornea. This may result from a variety of bacterial, viral or fungal infections, or may be non-infective, for example due to trauma or associated with an auto-immune disease.

Inflammation of the cornea commonly presents as

  • a painful red eye with reduced visual acuity due to cellular infiltration and later, corneal oedema
  • blood vessel dilatation is typically concentrated around the limbus - circumcorneal injection
  • often, the conjunctiva is also inflamed - keratoconjunctivitis
  • discharge is usually present and may be watery, mucoid or purulent; notably, it is absent in keratoconjunctivitis sicca
  • pupil may be small due to reflexive miosis; photophobia is common
  • fluorescein readily demonstrates any ulceration (an epithelial breach)

Keratitis an cause significant loss of vision from (1):

  • scarring
  • astigmatism

Complications leading to blindness (2)

  • corneal perforation,
  • choroidal detachment
  • endophthalmitis,
  • phthisis

Corneal ulceration is an ophthalmologic emergency.

  • the cause must be identified before treatment starts since some therapies are beneficial in one circumstance but are aggravating in another
  • refer the same day for urgent ophthalmological review as delay in treatment may result in loss of sight.

Notes:

  • corneal ulceration may occur without keratitis e.g. when a corneal ulcer is secondary to trauma
  • non-infective keratitis may occur in autoimmune diseases
  • risk factors include for development of keratitis include:
    • tear insufficiency,
    • malnutrition,
    • Vitamin A deficiency
      • Vitamin A in combination with zinc maintains conjunctival and corneal surfaces (3)
    • contact lens use
  • microbial keratitis is an ophthalmological emergency which may lead to loss of vision (4)
    • a Japanese study revealed that (5):
      • causative agents of microbial keratitis were
        • gram-positive bacteria (commonest)
        • gram-negative bacteria
        • fungi; and
        • acanthamoeba
      • contact lens wear was the most common risk factor for development of microbial keratitis in this study

Reference:

  1. Tuli SS, et al. Ocul Surf. 2007 Jan;5(1):23-39. Science and strategy for preventing and managing corneal ulceration.
  2. Whitcher JP et al. Corneal blindness: a global perspective. Bulletin of the World Health Organization, 2001; 79 (3).
  3. Heinz C, et al.Corneal perforation associated with vitamin-A-deficiency. Ophthalmologe. 2004; 101(6):614-7.
  4. Curr Opin Infect Dis. 2007 Apr;20(2):129-41
  5. Toshida H et al. Trends in microbial keratitis in Japan.Eye Contact Lens. 2007 Mar;33(2):70-3