II. Pathophysiology

  1. Trauma to eye results in infraorbital artery distribution Hemorrhage
  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 inschemia results when Intraocular Pressure increases above central Retinal artery pressure

III. Imaging

IV. Management: Lateral Canthotomy Indications

  1. Retrobulbar Hematoma and
  2. Primary indications
    1. Proptosis
    2. Intraocular Pressure >40 mmHg
    3. Decreased Visual Acuity
  3. 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

V. References

  1. Peak in O'Connor (2012) Medscape: EMedicine
    1. http://emedicine.medscape.com/article/799528-overview#showall
  2. Wu in Majoewsky (2012) EM:Rap 12(11):11-12

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