Oculoplastics and Orbital Disease
Core concepts
Know eyelid anatomy (orbicularis, levator, Müller muscle) and the causes of ptosis (aponeurotic, myogenic, neurogenic, mechanical). Understand orbital cellulitis vs. preseptal cellulitis (the orbital septum is the dividing line; orbital involvement has proptosis, restricted motility, and risk of cavernous sinus thrombosis). Know thyroid eye disease (Graves orbitopathy - proptosis, lid retraction, optic neuropathy), orbital tumors (lymphoma, hemangioma, metastasis), and lacrimal system disorders (dacryocystitis, nasolacrimal duct obstruction).
Traps
A classic trap is mistaking preseptal for orbital cellulitis - orbital cellulitis needs IV antibiotics and imaging, and can threaten vision. Another trap is Graves orbitopathy - smoking worsens it, and optic neuropathy is an emergency requiring steroids or decompression. Also know lacrimal gland tumors vs. dacryoadenitis.
Worked example
A child with eyelid swelling, fever, and proptosis after a sinus infection. Rule of thumb: proptosis + restricted motility = orbital cellulitis; obtain CT, start IV antibiotics, and involve ENT for sinus drainage.