HomePublicInformationCommonconditionsBlepharitisBlepharitisOverview:Whatisblepharitis?Blepharitisisarelativelycommoninflammatoryconditionwhichaffectstheeyelidmargin(theedgeoftheeyelid).Itcanaffecttheeyelashroots(thisisreferredtoas“anteriorblepharitis”)andtheareaimmediatelybehindthis(thisisreferredtoas“posteriorblepharitis”).In“posteriorblepharitis”,thetinymeibomianglands(glandsresponsibleforthesecretionofanoilysubstancethathelpstopreventthelayeroftearsonthefrontoftheeyefromevaporatinginbetweenblinks)thatliewithintheeyelidsmayalsobeaffected–thisisreferredtoas“meibomianitis”.Thiscausesafrothydischargebehindtheeyelashes.Whatcausesblepharitis?Inmostpatients,thecauseisunknown.In“anteriorblepharitis”,excessivebacterialactivitymayplayarole.“Posteriorblepharitis”ismorecommonlyseenamongpatientswithskinconditionssuchasseborrhoeicdermatitis(whichisassociatedwith“dandruff”)androsacea(whichcausesarednessoftheskinofthecheeksandnose).Whatarethefeaturesofblepharitis?Thefollowingsymptomsandsignsaretypical:(i)Rednessanditchingoftheeyelidmargins(ii)Irritationand‘dryeye’symptomsThisoccursbecause,withoutadequateoilysecretionsinthetearfilmonthesurfaceoftheeye,thetearfilmquicklyevaporates.Thisistypicallyworseoutsideinthewindorinanair-conditionedenvironment.Oneoftheaimsoftreatmentisthereforetheimprovementofboththequalityandquantityoftheoilymeibomianglandsecretions(seebelow).(iii)ExcessivewateringoftheeyesAnirregulartearfilm(duetofailureoftheoilymeibomiansecretions)canleadtolocalisedareasofdrynessonthesurfaceoftheeye.Thiscanstimulatetheexcessiveproductionthewaterycomponentofthetears,withpatientssometimesdescribingaveryuncomfortable‘streaming’oftheeyes.Intheabsenceofthecorrectproportionsofmucus,wateryandoilycomponentsofthetears,excessivewateringdoesnotadequatelylubricatethesurfaceoftheeye(thecornea),andfurthercyclesofexcessivewateringcanoccurasareflex.(iv)CystformationwithintheeyelidsWithblockagesoftheductswhichconducttheoilswithinthemeibomianglandstothesurfaceoftheeye(thisismorelikelytooccu