A 24-year-old man was struck in the right orbit by a cricket ball. He has double vision on looking up, numbness over the right cheek, and 3 mm of enophthalmos. CT shows a defect in the orbital floor with herniation of orbital fat. Which finding is the principal indication for early surgical repair of the floor?
- A Subconjunctival haemorrhage
- B Diplopia in primary gaze with positive forced duction test ✓
- C Periorbital ecchymosis
- D Infraorbital nerve paraesthesia alone
Correct answer: B. Diplopia in primary gaze with positive forced duction test
Explanation
Entrapment of the inferior rectus and perimuscular tissue in a blowout fracture causes restriction of elevation, and when this produces diplopia in primary or down gaze with a positive forced duction test, early repair within about two weeks is indicated to prevent permanent fibrosis. Infraorbital anaesthesia usually recovers spontaneously, and ecchymosis or subconjunctival bleeding never mandate surgery. Significant enophthalmos is a further indication but diplopia with a positive forced duction test is the classic urgent driver.
Reference: Kanski's Clinical Ophthalmology, 9th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.