Which single finding on examination MOST reliably differentiates orbital cellulitis from preseptal cellulitis?
- A Fever and leukocytosis
- B Eyelid oedema and erythema
- C Proptosis with painful restricted ocular motility ✓
- D Recent history of sinusitis
Correct answer: C. Proptosis with painful restricted ocular motility
Explanation
Preseptal cellulitis involves tissues anterior to the orbital septum, so the globe and its movements remain unaffected. Proptosis, chemosis, painful or limited ocular movements, visual impairment, and resistance to retropulsion indicate posterior septal involvement and define orbital cellulitis. Fever, lid swelling, and antecedent sinusitis occur in both conditions and therefore cannot separate them.
Reference: Khurana's Comprehensive Ophthalmology, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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