In orbital blowout fracture involving the orbital floor, the most important early surgical indication (within 2 weeks) regardless of diplopia severity is:

• A Enophthalmos > 2 mm immediately post-injury
• B Fracture occupying > 50% of the orbital floor area on CT scan
• C Vertical diplopia persisting beyond 2 weeks with positive forced duction test
• D Trapdoor fracture with incarcerated inferior rectus causing the 'white-eyed blowout' with oculocardiac reflex (bradycardia, nausea, syncope) ✓

Explanation

The 'white-eyed blowout' fracture (trapdoor fracture) is a pediatric emergency requiring urgent surgical repair. In children, the orbital bones are more elastic, causing a trapdoor mechanism where the fractured floor springs back, incarcerating periorbital fat or the inferior rectus muscle. The entrapped tissue causes oculocardiac reflex (vagal response — bradycardia, nausea, vomiting, syncope) on attempted upgaze. Despite minimal external ecchymosis ('white-eyed'), there is severe restriction of upgaze and incarcerated tissue undergoes ischemic necrosis if not released within 24-48 hours. Delay causes permanent fibrosis and irreversible diplopia. Adults with trapdoor fracture also benefit from early repair but the timeframe is more urgent in children due to tissue vulnerability.

Reference: Khurana Comprehensive Ophthalmology, 7th ed.

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Written and medically reviewed by the StethoPrep medical team.