Last reviewed: 16 May 2021
Last updated: 06 Aug 2020



History and exam

Key diagnostic factors

  • presence of risk factors
  • corneal infiltrate
  • corneal ulcer
  • dendritic or geographical epithelial lesion
  • periocular skin lesions
  • multifocal corneal ulcer with feathery edges
  • corneal perineuritis
  • interstitial keratitis

Other diagnostic factors

  • redness
  • pain
  • increased lacrimation
  • lid oedema
  • discharge
  • decreased visual acuity
  • photophobia
  • high intraocular pressure
  • history of herpes simplex virus or varicella zoster virus infection
  • multiple old stromal scars
  • iris transillumination
  • corneal hypoaesthesia

Risk factors

  • contact lens wear
  • corneal trauma
  • corneal abrasion/erosion
  • trichiasis
  • blepharitis
  • dry eye
  • poor eyelid function
  • previous herpetic disease
  • exposure keratitis
  • recurrent corneal erosions
  • contaminated water exposure
  • topical corticosteroid use
  • topical anaesthetic use
  • previous eye surgery
  • immunocompromised
  • history of autoimmune disease

Diagnostic investigations

1st investigations to order

  • corneal scraping: microscope slide
  • corneal scraping: cultures and sensitivity

Emerging tests

  • corneal scraping: polymerase chain reaction

Treatment algorithm


Director of Refractive Surgery

The Wilmer Eye Institute

The Johns Hopkins Hospital




KSB declares that he has no competing interests.

Assistant Professor

Cornea, External Disease and Refractive Surgery

Loma Linda University Eye Institute

Loma Linda University

Loma Linda



FSH declares that he has no competing interests.

Dr Kraig Scot Bower and Dr Frank S. Hwang would like to gratefully acknowledge Dr Julie Freidlin Leigh, a previous contributor to this topic.


JFL declares that she has no competing interests.

Peer reviewersVIEW ALL

Proctor Fellow in Cornea and External Disease

Francis I. Proctor Foundation

University of California

San Francisco



MC declares that she has no competing interests.

Senior Lecturer & Consultant

Ophthalmic Surgeon

Division of Infection, Inflammation & Immunity

University of Southampton

Southampton General Hospital




PH declares that he has no competing interests.

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