Hordeolum (Sty): Infection involving hair follicle of the eyelash. Internal hordeolum (relatively large, affecting the meibomian glands; may point toward the skin or toward the conjunctive) and external hordeolum (also known as a "sty;" smaller and more superficial; an infection of the glands of Moll or Zeiss; painful; always points toward the skin side of the lid margin).
Pathophysiology
There is usually underlying meibomitis with thickening and stasis of gland secretions with resultant inspissation of the Zeis or meibomian gland orifices. Stasis of the secretions leads to secondary infection, usually by Staphylococcus aureus. Histologically, hordeola represent focal collections of polymorphonuclear leukocytes and necrotic debris (ie, an abscess).
Hordeola should not be confused with chalazia, which represent focal, chronic, lipogranulomatous inflammation of the Zeis or meibomian glands. Chalazia form when underlying meibomitis results in stasis of gland secretions, and the contents of the glands (sebum) are released into the tarsus and adjacent tissues to incite a noninfectious inflammatory reaction. Histologically, chalazia appear as a granulomatous reaction (ie, histiocytes, multinucleated giant cells) surrounding clear spaces that were once occupied by sebum/lipid before they were dissolved by the solvents used for tissue processing, hence the term lipogranuloma.
Both types of hordeola are treated with warm compresses for 10-15 minutes 3-4 times a day; if the condition does not improve within 48 hours, incision and drainage of the pus is indicated. Antibacterial ophthalmic ointment is also helpful.