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Last updated: September 14, 2021

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Keratitis is inflammation of the cornea, a clear and transparent covering over the iris and pupil. Important forms of keratitis include bacterial, herpes zoster, herpes simplex, and Acanthamoeba keratitis. Most corneal injuries and infections are associated with severe pain, although sometimes pain is absent. Other findings include irritation, eye redness, watery or purulent secretion, and impaired vision. Diagnosis is usually based on clinical findings and slit-lamp examination. Keratitis is an emergent disorder that can lead to irreversible vision loss left untreated.

Keratitis overview
Characteristic features Therapy
Bacterial keratitis
  • Most common form of keratitis
  • ↑ Risk with wearing contact lenses
  • Purulent discharge and/or hypopyon
  • Round corneal infiltrate or ulcer
Herpes zoster keratitis
  • ↓ Corneal sensation
  • Punctate lesions on the corneal surface (early disease)
  • Vesicular eruption on forehead, bridge, and tip of the nose
Herpes simplex keratitis
  • Dendritic or geographic corneal ulcer
Acanthamoeba keratitis
  • ↑ Risk with wearing contact lenses
  • Corneal ring infiltrate

Bacterial keratitis should be treated as an ophthalmic emergency because of the risk of irreversible vision loss.

Herpes simplex keratitis

Glucocorticoids should not be used in initial treatment of dendritic epithelial keratitis!

Herpes zoster keratitis [7][8]

See also “Herpes zoster ophthalmicus.”


See “Epidemic keratoconjunctivitis.”

  • Etiology: Acanthamoeba infection [9]
  • Characteristics
    • Rare condition
    • Primarily occurs in immunocompetent contact lens wearers
    • Progressive course for several weeks despite an attempt of antibiotic treatment
  • Clinical features
  • Diagnostics
    • Slit-lamp examination and/or fluorescein staining: features of epithelitis and stromal disease
    • Culture and microscopy of eye scraping
    • Pathogen detection is often difficult.
  • Treatment



Anesthetic eye drops should only be applied for diagnostic purposes Do not initiate pain therapy as improper use can lead to epithelial damage. Elimination of the protective corneal reflex can result in further corneal damage.

Exposure keratopathy

  • Definition: keratitis caused by the inability to completely close the eyelids resulting in corneal drying
  • Etiology: mainly caused by damage to the facial nerve, e.g., from a stroke

Neurotrophic keratopathy

  1. Acanthamoeba Keratitis. Updated: June 5, 2017. Accessed: August 28, 2017.
  2. Lorenzo-Morales J, Khan NA, Walochnik J. An update on acanthamoeba keratitis: diagnosis, pathogenesis and treatment. Parasite. 2015; 22 (10). doi: 10.1051/parasite/2015010 . | Open in Read by QxMD
  3. Olver J, Cassidy L, Jutley G. Ophthalmology at a Glance. John Wiley & Sons ; 2014
  4. Herpes Simplex Virus Keratitis: A Treatment Guideline. Updated: June 1, 2014. Accessed: March 2, 2021.
  5. Herpes Zoster Ophthalmicus. . Accessed: August 28, 2017.
  6. Shaik S, Ta CN. Evaluation and management of herpes zoster ophthalmicus. Am Fam Physician. 2002; 66 (9): p.1723-1730.
  7. Al-Mujaini A, Al-Kharusi N, Thakral A, Wali UK. Bacterial keratitis: Perspective on epidemiology, clinico-pathogenesis, diagnosis and treatment. Sultan Qaboos Univ Med J.. 2009; 9 (2): p.184-195.
  8. Bacterial Keratitis Preferred Practice Pattern Guideline. Updated: October 1, 2013. Accessed: August 26, 2017.
  9. Eltis M. Contact-lens-related microbial keratitis: case report and review. J Optom. 2011; 4 (4): p.122-127. doi: 10.1016/S1888-4296(11)70053-X . | Open in Read by QxMD
  10. Al-Mujaini A, Al-Kharusi N, Thakral A, Wali UK. Bacterial keratitis: perspective on epidemiology, clinico-pathogenesis, diagnosis and treatment.. Sultan Qaboos University medical journal. 2009; 9 (2): p.184-95.
  11. Ansari Z, Miller D, Galor A. Current thoughts in fungal keratitis: Diagnosis and treatment. Curr Fungal Infect Rep. 2013; 7 (3): p.209–218. doi: 10.1007/s12281-013-0150-110.1007/s12281-013-0150-1 . | Open in Read by QxMD