This disorder is an ocular emergency and remains one of the major causes of blindness around the world.
Main risk factors include corneal trauma, contact lens wear, and breakdown of the corneal epithelium.
The diagnosis depends on a careful history, slit-lamp examination, and corneal scraping cultures.
Treatment consists of topical antimicrobial agents that may be supplemented by pupil-dilating agents, analgesics, corticosteroids, and systemic antimicrobials as needed.
Complications include corneal scarring, perforation, and endophthalmitis.
Infectious keratitis refers to microbial invasion of the cornea causing inflammation and damage to the corneal epithelium, stroma, or endothelium. Non-infectious keratitis is, for the most part, rare.
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
- increased lacrimation
- lid oedema
- decreased visual acuity
- high intraocular pressure
- history of herpes simplex virus or varicella zoster virus infection
- multiple old stromal scars
- iris transillumination
- corneal hypoaesthesia
- contact lens wear
- corneal trauma
- corneal abrasion/erosion
- 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
- history of autoimmune disease
1st investigations to order
- corneal scraping: microscope slide
- corneal scraping: cultures and sensitivity
Investigations to consider
- HIV test
- corneal scraping: polymerase chain reaction
bacterial (presumed): high risk
recurrent herpetic infection
corneal scarring impairing vision
Kraig Scot Bower, MD
Director of Refractive Surgery
The Wilmer Eye Institute
The Johns Hopkins Hospital
KSB declares that he has no competing interests.
Frank S. Hwang, MD
Cornea, External Disease and Refractive Surgery
Loma Linda University Eye Institute
Loma Linda University
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.
Matilda Chan, MD, PhD
Proctor Fellow in Cornea and External Disease
Francis I. Proctor Foundation
University of California
MC declares that she has no competing interests.
Parwez Hossain, MD, PhD, FRCOphth, FRCS (Ed)
Senior Lecturer & Consultant
Division of Infection, Inflammation & Immunity
University of Southampton
Southampton General Hospital
PH declares that he has no competing interests.
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