A 6-year-old boy presents with fever, right eyelid swelling, and redness of 3 days duration. On examination there is right axial proptosis, restriction of ocular movements in all directions, and visual acuity of 6/36 in the right eye. Which additional finding would MOST strongly support a diagnosis of orbital cellulitis rather than preseptal cellulitis?

• A Restricted ocular motility with proptosis ✓
• B Tenderness over the ethmoid sinuses
• C Swelling confined anterior to the orbital septum
• D Conjunctival injection without chemosis

Explanation

Orbital cellulitis involves structures posterior to the orbital septum and produces proptosis, painful restriction of extraocular movements, chemosis, and often visual loss. Preseptal cellulitis is limited to tissues anterior to the septum, so lid swelling occurs without proptosis or motility restriction. The most common source in children is ethmoid sinusitis, but ethmoid tenderness alone does not separate the two conditions. Restricted motility with proptosis is the discriminating sign.

Reference: Kanski's Clinical Ophthalmology, 10th ed.

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Written and medically reviewed by the StethoPrep medical team.