Corneal Foreign Body

Aka: Corneal Foreign Body, Cornea Foreign Body

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II. Pathophysiology

  1. Usually clipped or broken metallic particles
  2. Particles embed in Cornea with significant force

III. Management

  1. Check Visual Acuity prior to removal
  2. Apply Topical Anesthetic (e.g. 0.5% tetracaine, proparacaine) to affected eye
  3. Attempt removal with Lactated Ringers (preferred) or sterile saline (but is more acidic) irrigation
    1. Direct intravenous tubing from crystalloid bag tangential to Corneal surface
    2. Flow directed toward foreign body may dislodge it
  4. Attempt removal with moistened sterile cotton swab
  5. Attempt removal with 18 to 25 gauge needle tip (or similar Corneal spud)
    1. May bend needle to 45 degrees for better control at Corneal surface
    2. Grip needle (or spud) as with a pencil, between the thumb and index finger of the dominant hand
    3. Brace hand against patient's face
    4. Position 25 gauge needle parallel to the Corneal surface, approaching from lateral aspect
    5. Use magnifying loops (or Slit Lamp)
    6. Gently flick out the foreign body
  6. Battery operated burr tool
    1. Indications
      1. Corneal Foreign Body removal refractory to other measures
      2. Rust ring remaining after metallic Foreign Body Removal (or refer to ophthalmology for removal)
    2. Technique
      1. Select a burr size slightly larger than the foreign body
      2. Perform under magnification (Slit Lamp preferred)
      3. Hold the burr tool, as with a pencil, between thumb and index finger
      4. Turn the drill on, and gradually approach the foreign body from tangential position
      5. Gently debride the foreign body with very short bursts of applying burr (e.g. a few drill rotations)
      6. Re-examine the Corneal surface
    3. Many ophthalmologists do not recommend burr use by emergency providers
      1. Potential for significant Corneal damage and scarring
      2. Risk of further embedding Ocular Foreign Body
  7. If unable to remove
    1. Refer to Ophthalmology
  8. Prophylactic Topical Antibiotic coverage
    1. See Corneal Abrasion
    2. Apply 4 times daily until epithelium heals (typically 4-5 days)
    3. Contact Lens wearers: Fluoroquinolone (e.g. Ofloxacin) drops for Pseudomonas coverage
    4. No Contact Lens Use: Erythromycin Ointment
  9. Analgesia for abrasions >3 mm long
    1. See Corneal Abrasion
    2. Ocular NSAIDs (e.g. Ketorolac Ophthalmic)
    3. Long acting Cycloplegic (e.g. .25% Isopto Hyoscine, Cyclopentolate)
      1. Avoid in shallow anterior chamber and closed angle Glaucoma
    4. AVOID Topical Anesthetics or steroids
      1. Interfere with epithelium healing
      2. However, brief use of Topical Anesthetic is thought safe (ACEP consensus guideline)
        1. Total 1.5 to 2 ml over first 24 hours for simple Corneal Abrasions
        2. Green (2024) Ann Emerg Med 83(5):477-89 +PMID: 38323950 [PubMed]
  10. Eye patches
    1. Contraindicated with infection risk (e.g. organic foreign body, Contact Lens use)
    2. Not indicated in most cases
    3. May consider with large, painful Corneal defects with close ophthalmology follow-up arranged
  11. Reevaluate patient in 24-48 hours
    1. Signs of infection
    2. Adequate healing without signs of Corneal Ulcer
      1. Fluorescein staining should resolve by 72 hours

IV. Management: Ophthalmology referral indications

  1. Difficult Foreign Body Removal
  2. Rust Ring formation at Cornea
  3. Signs of perforation of globe with foreign body
  4. Signs of Corneal Ulcer formation
    1. Haze at base of Corneal defect
    2. Fluorescein staining persists >72 hours
  5. Central Corneal defects

V. Complications

  1. Rust Ring
    1. Occurs with iron foreign bodies
    2. Onset in 2-4 hours after embedding
    3. Complete rust ring forms in 8 hours
    4. Burr tool is available in many Emergency Departments
      1. However risk of Vision Loss if Bowman's Membrane is disrupted
      2. Consider application or Antibiotic ointment (e.g. Erythromycin) and referral to ophthalmology for the next day
  2. Prolonged foreign body
    1. Infection risk if embedded >2-4 days
      1. Results in Corneal Ulceration and scarring
    2. Requires Ophthalmology referral
  3. Globe Perforation
    1. Anterior chamber appears more shallow
    2. Leakage of fluid from site of foreign body embedding

VI. References

  1. Baxter, Williams, Mehta (2025) Crit Dec Emerg Med 39(11): 28-35

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