Editing Blepharitis (section)

== Mechanism ==
The mechanism by which the bacteria causes symptoms of blepharitis is not fully understood and may include direct irritation of bacterial toxins and/or enhanced cell-mediated immunity to ''[[Staphylococcus aureus|S. aureus]]''.

Staphylococcal blepharitis is caused by an infection of the anterior portion of the eyelid by [[Staphylococcus|Staphylococcal bacteria]].<ref name=smolin/> In a study of ocular flora, 46% to 51% of those diagnosed with staphylococcal blepharitis had cultures positive for Staphylococcus aureus in comparison to 8% of normal patients.<ref name=":0" /> Staphylococcal blepharitis may start in childhood and continue into adulthood.<ref>{{cite web|url=http://www.avclinic.com/blepharitis.htm|title=Blepharitis|publisher=Angeles Vision Clinic|archive-url=https://web.archive.org/web/20120504114556/http://www.avclinic.com/blepharitis.htm|archive-date=4 May 2012|url-status=dead|access-date=21 December 2012}}</ref> It is commonly recurrent and it requires special medical care. The prevalence of ''S. aureus'' in the conjunctival sac and on the lid margin varies among countries, likely due to differences in climate and environment.<ref name="smolin">{{cite journal | vauthors = Smolin G, Okumoto M | title = Staphylococcal blepharitis | journal = Archives of Ophthalmology | volume = 95 | issue = 5 | pages = 812–816 | date = May 1977 | pmid = 324453 | doi = 10.1001/archopht.1977.04450050090009 }}</ref> Seborrheic blepharitis is characterized by less inflammation than Staphylococcal blepharitis; however, it causes more excess oil or greasy scaling. [[Meibomian gland|Meibomian gland dysfunction]] is a result of abnormalities of the meibomian glands and altered secretion of [[meibum]], which plays an imperative role in lagging the evaporation of tear films and smoothing of the tear film to produce an even optical surface. Posterior blepharitis is an inflammation of the eyelids, secondary to dysfunction of the [[meibomian gland]]s. Like anterior blepharitis, it is a bilateral chronic condition and may be associated with skin [[rosacea]].<ref name="vaughan2" />  There is growing evidence that, in some cases, it is caused by [[demodex]] [[mite]]s.<ref>{{cite journal | vauthors = Liu J, Sheha H, Tseng SC | title = Pathogenic role of Demodex mites in blepharitis | journal = Current Opinion in Allergy and Clinical Immunology | volume = 10 | issue = 5 | pages = 505–510 | date = October 2010 | pmid = 20689407 | pmc = 2946818 | doi = 10.1097/aci.0b013e32833df9f4 }}</ref>