Corneal Burn

Basics

Description

  • Inappropriate exposure of cornea to chemicals, heat, cold, electrical, or radiant energy causing damage to the cornea and often extending to adjacent structures
  • Severity of injury related to duration of exposure, type of agent, anion concentration, pH level of solution
  • Alkalis:
    • Cause immediate rise in pH level
    • Highly soluble in lipids, so rapidly penetrate the eye, causing severe corneal injury and continue to penetrate over time if no intervention undertaken
    • Penetration can occur in <1 min
    • Exception: Calcium alkalis penetrate relatively poorly, secondary to soap formation; can cause corneal opacification, so may appear worse but actually have better prognosis than other alkali burns
  • Acids:
    • Immediately coagulate proteins of corneal epithelium
    • Cause opacification
    • Coagulation produces barrier to deeper penetration
    • Exception: Lipophilicity of hydrofluoric (HF) acid causes it to act similar to a base with more rapid penetration
  • Thermal burns:
    • Affect eyelids more than globe due to reflex blinking and Bell phenomenon (eyes roll up and outward)
    • Cause direct injury to cornea
    • Damage primarily depends on duration and intensity of heat
  • Electrical injury:
    • Occurs with current flow through head, with input at or near eye
  • Radiation injury:
    • Due to ultraviolet light exposure to cornea
    • Often bilateral
    • Symptoms usually increase 6–12 hr after exposure

Etiology

  • Alkalis:
    • Ammonia:
      • Fertilizer, refrigerant, household ammonia, cleansing agents
    • Potassium hydroxide:
      • Caustic potash
    • Magnesium hydroxide:
      • Sparklers, flares, fireworks
    • Lye: NaOH:
      • Caustic soda, drain cleaners
    • Lime: CaOH2 or MgOH2:
      • Fresh lime, quicklime, calcium hydrate, slaked lime, hydrated lime, plaster, mortar, cement, whitewash
    • Nonspecific alkali:
      • Motor vehicle airbag on inflation releases alkali
      • Detergent pods
  • Acids:
    • Sulfuric acid: H2SO4:
      • Car battery acid, toilet cleaner
    • Sulfurous acid: H2SO3:
      • Preservatives (fruit and vegetable)
    • Acetic acid: CH3CO2H:
      • Vinegar
  • Bleach
  • Refrigerants:
    • HF acid:
      • Etching silicon/glass
      • Cleaning brick
      • Electropolishing metals
      • Control of fermentation in breweries
      • Commercial/household rust removal
  • Thermal:
    • Hot liquids, molten metal
    • Flames
    • Hot smoke/gases
    • Flash burn
    • Steam
    • Cigarette burns
  • Radiation:
    • Sun lamps
    • Tanning booths
    • High-altitude sunlight
    • Reflection off snow/water
    • Arc welding

Pediatric Considerations
Consider child abuse or neglect

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