Oculoplastics and Orbit
Core concepts
Know orbital anatomy, including the bony walls, fissures, and contents. Understand eyelid anatomy and function, lacrimal drainage, and the principles of ptosis repair. Recognise orbital cellulitis, thyroid eye disease, and orbital tumours. Learn the approach to proptosis, enophthalmos, and diplopia. Understand eyelid malpositions (entropion, ectropion) and their surgical correction. Know when imaging is indicated.
Traps
Examiners test distinguishing orbital cellulitis from preseptal cellulitis; orbital involvement threatens vision. Remember thyroid eye disease causes restrictive myopathy, commonly inferior rectus. Do not confuse involutional entropion with spastic entropion. Know that orbital imaging is mandatory for unexplained proptosis.
Worked example
A child has eyelid swelling, fever, and limited eye movement. Suspect orbital cellulitis; obtain CT and start intravenous antibiotics. Rule of thumb: limited motility or proptosis indicates orbital, not preseptal, involvement.