Eyes & Vision

Infective Keratitis

Infective keratitis is a sight-threatening corneal infection causing a painful red photophobic eye with an infiltrate or ulcer; contact-lens-associated disease and Acanthamoeba require emergency ophthalmology, microbiological assessment and specialist antimicrobial treatment.

Definition

Infective keratitis is infection and inflammation of the cornea, usually with an epithelial defect over a stromal infiltrate or ulcer. It may be bacterial, fungal, Acanthamoeba or viral such as herpes simplex, and threatens vision through scarring, stromal melt, perforation and secondary intraocular inflammation.

First principles

The cornea is transparent and has little vascular reserve

The cornea must remain clear to focus light, and its avascular stroma has limited direct blood supply. Infection and inflammatory infiltrate therefore reduce vision directly, while stromal enzymes can melt tissue, perforate the globe and leave a central scar even after infection is controlled.

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