The lowly chalazion.

Chalazia are localized cysts of chronic lipogranulomatous inflammation arising from the obstruction of sebaceous glands of the eyelid tarsal plate, including the Meibomian gland (deep chalazion) or Zeis gland (superficial chalazion). This disease entity is differentiated from the hordeolum (stye), an acute purulent localized swelling of the eyelid often associated with an eyelash follicle, Zeis gland, or Moll gland obstruction and infection. Ambiguously, the chalazion, hordeolum, and blepharitis are commonly categorized and described on a continuum in the literature. While it is one of the most common eyelid disorders across all age demographics, the chalazion remains largely understudied and pathophysiological, epidemiological, and therapeutic findings exist fragmented in the literature. We discuss current understandings of the chalazion and provide current best practice guidelines supported by clinical anecdotal evidence.