Two hours after blunt orbital trauma, a patient has tense proptosis, a hard orbit, visual decline from 6/6 to 6/36, an afferent pupillary defect, and intraocular pressure of 52 mmHg unresponsive to medical therapy. CT shows a retrobulbar haemorrhage. What is the definitive emergency intervention?
- A Repeat CT after six hours of observation
- B Intravenous mannitol infusion alone
- C Lateral canthotomy with inferior cantholysis at the bedside ✓
- D Immediate exploration of the orbital floor
Correct answer: C. Lateral canthotomy with inferior cantholysis at the bedside
Explanation
Retrobulbar haemorrhage causes orbital compartment syndrome: raised intraocular pressure, tense proptosis, and vision-threatening optic nerve and retinal ischaemia. Once vision declines despite maximal medical therapy, bedside lateral canthotomy with inferior cantholysis must be performed immediately to decompress the orbit; delay beyond about two hours risks permanent visual loss. Mannitol and acetazolamide buy time only, and floor exploration does not relieve the compartment pressure.
Reference: Kanski's Clinical Ophthalmology, 9th ed.
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Written and medically reviewed by the StethoPrep medical team.