Keratitis

Inflammation of the cornea, typically presenting with ocular pain, photophobia, decreased visual acuity, and ciliary injection, and potentially progressing to corneal ulceration, perforation, or scarring.

Causes

• Infectious causes

  • Bacterial keratitis

    • Pseudomonas aeruginosa (especially associated with contact lens use)

    • Staphylococcus aureus

    • Streptococcus pneumoniae

    • Other bacterial pathogens

  • Viral keratitis

    • Herpes simplex virus (HSV)

    • Herpes zoster virus (HZV)

  • Fungal keratitis

    • Fusarium

    • Aspergillus

    • Other fungal organisms

  • Parasitic keratitis

    • Acanthamoeba infection (often associated with contact lens use and contaminated water exposure)

• Noninfectious causes

  • Contact lens–related corneal injury or hypoxia

  • Eye trauma

  • Corneal abrasion

  • Foreign body injury

  • Dry eye disease

  • Lagophthalmos causing exposure keratitis

  • Incomplete eyelid closure

  • Autoimmune or inflammatory ocular surface disease

• Environmental and physical causes

  • Snow blindness (ultraviolet radiation exposure)

  • Welders' arc eye (photokeratitis)

  • Chemical exposure

  • Excessive ocular surface irritation