Oculoplastics and Orbit
Core concepts
Know eyelid anatomy and the lacrimal system. Understand common eyelid lesions: chalazion, hordeolum, basal cell carcinoma, squamous cell carcinoma, and sebaceous carcinoma. Learn the signs of orbital disease: proptosis, restricted motility, and optic nerve compromise. Understand thyroid eye disease (Graves orbitopathy) and its management. Know orbital cellulitis versus preseptal cellulitis and when imaging is needed. Understand ptosis causes (aponeurotic, myogenic, neurogenic, mechanical) and entropion/ectropion.
Traps
Preseptal cellulitis does not cause proptosis, ophthalmoplegia, or vision loss; orbital cellulitis does and needs urgent imaging and IV antibiotics. A "chalazion" that recurs in an older patient should raise suspicion for sebaceous carcinoma. Do not miss orbital compartment syndrome with a tight orbit after trauma. In thyroid eye disease, smoking worsens the disease.
Rule of thumb
Any orbital sign (proptosis, motility restriction, optic neuropathy) with fever or sinus symptoms = orbital cellulitis until proven otherwise; obtain CT and start IV antibiotics.
Worked example
A child with sinusitis develops eyelid swelling, proptosis, and pain with eye movement. This is orbital cellulitis; obtain CT of orbits and sinuses and admit for IV antibiotics.