II. Pathophysiology

  1. Trauma to eye results in infraorbital artery distribution Hemorrhage
    1. Even minor Trauma may result in Retrobulbar Hematoma for those with bleeding risk (e.g. Anticoagulation)
  2. Orbit is a closed space
    1. Surrounded by bone in all planes except anteriorly
    2. Anterior margin is blocked by the medial and lateral canthal tendons which hold the globe in the orbit
  3. Hemorrhage results in increased orbital pressures
  4. Compartment Syndrome results if these pressures are not decompressed
    1. Compression of artery and Optic Nerve
    2. Retinal ischemia results when Intraocular Pressure increases above central Retinal artery pressure
      1. Irreversible injury may start within 60-90 minutes of ischemia onset

III. Signs: Unilateral Findings

  1. Eye Pain
  2. Decreased Visual Acuity
  3. Proptosis
  4. Diffuse Subconjunctival Hemorrhage
  5. Decreased Extraocular Movement
  6. Increased introcular pressure >40 mmHg
  7. Globe feels "hard as a rock"
    1. Avoid applying significant pressure to eye
  8. Afferent pupil defect
    1. Associated with Optic Nerve injury
  9. Difficult Eyelid opening

IV. Imaging

  1. CT Head
  2. Bedside Orbital Ultrasound
    1. Exercise caution to prevent significant pressure on globe

V. Management: General

  1. Emergent opthalmology Consultation for surgical decompression
  2. Emergent Lateral Canthotomy (see below) if indicated
    1. See Lateral Canthotomy

VI. Management: Lateral Canthotomy Indications

  1. See Lateral Canthotomy
  2. Retrobulbar Hematoma and
  3. Primary indications
    1. Proptosis
    2. Intraocular Pressure >40 mmHg
    3. Decreased Visual Acuity
  4. Secondary indications
    1. Afferent Pupillary Defect (see Orbital Ultrasound)
    2. Eye Pain
    3. Funduscopic changes
      1. Cherry red Macula
      2. Pallor of the nerve head

VII. References

  1. Dreis (2020) Crit Dec Emerg Med 34(7):3-21
  2. Werner and St Peter in Swadron (2023) EM:Rap 23(4): 7-8
  3. Peak in O'Connor (2012) Medscape: EMedicine
    1. http://emedicine.medscape.com/article/799528-overview#showall
  4. Wu in Herbert (2012) EM:Rap 12(11):11-12

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