II. Pathophysiology
-
Trauma to eye results in infraorbital artery distribution Hemorrhage
- Even minor Trauma may result in Retrobulbar Hematoma for those with bleeding risk (e.g. Anticoagulation)
- Orbit is a closed space
- Surrounded by bone in all planes except anteriorly
- Anterior margin is blocked by the medial and lateral canthal tendons which hold the globe in the orbit
- Hemorrhage results in increased orbital pressures
-
Compartment Syndrome results if these pressures are not decompressed
- Compression of artery and Optic Nerve
- Retinal ischemia results when Intraocular Pressure increases above central Retinal artery pressure
- Irreversible injury may start within 60-90 minutes of ischemia onset
III. Signs: Unilateral Findings
- Eye Pain
- Decreased Visual Acuity
- Proptosis
- Diffuse Subconjunctival Hemorrhage
- Decreased Extraocular Movement
- Increased introcular pressure >40 mmHg
- Globe feels "hard as a rock"
- Avoid applying significant pressure to eye
- Afferent pupil defect
- Associated with Optic Nerve injury
- Difficult Eyelid opening
IV. Imaging
- CT Head
- Bedside Orbital Ultrasound
- Exercise caution to prevent significant pressure on globe
V. Management: General
- Emergent opthalmology Consultation for surgical decompression
- Emergent Lateral Canthotomy (see below) if indicated
VI. Management: Lateral Canthotomy Indications
- See Lateral Canthotomy
- Retrobulbar Hematoma and
- Primary indications
- Secondary indications
- Afferent Pupillary Defect (see Orbital Ultrasound)
- Eye Pain
- Funduscopic changes
- Cherry red Macula
- Pallor of the nerve head
VII. References
- Dreis (2020) Crit Dec Emerg Med 34(7):3-21
- Werner and St Peter in Swadron (2023) EM:Rap 23(4): 7-8
- Peak in O'Connor (2012) Medscape: EMedicine
- Wu in Herbert (2012) EM:Rap 12(11):11-12