AIM:Todefinetheultrasonographicstructureofnormallowereyelidanatomiccompartmentsandtheirspacialrelationshipindynamicmotion.METHODS:Highresolutionultrasound(15MHz)wasperformedonthelowereyelidsof7normalsubjects.Movementsofthelowereyelidanditscompartmentswerevisualizedwithultrasound.Inaddition,themaximalexcursionareaofthelowereyelidfatcompartmentsandretractormotionswasmeasuredbeforeandaftermotion.RESULTS:Theorbicularismusclecouldbeseenasanecholucentstructurebetweenthedermisandtheechodencefatpads.Lowereyelidfatpadseemstobepidedinto2compartmentsasrangeofmotionanddirectionofmovementofeachofthemvaries.Itseemsthatthesecompartmentshavealsodifferentbehavior.Themeasuredprofileareaofthevisiblenormallowereyelidfatpadsduringmovementofglobefromup-gazetodown-gazedecreasedby50%.Orderofmovementoflowereyelidstructuresseemstobeasfollows:afterglobemovementfistweseeretractormovement,anteriororbitalfatpad,thenskinandseptum,andfinallymovementofinferiorfatpad.CONCLUSION:Ultrasoundrepresentsanoninvasivetoolforthevisualizationoflowereyelidmorphology.Expandingitsapplicationcouldhelpusunderstandthecompartmentalchangesinphysiologicaleyelidmovement,inaginganddiseasedstudypopulations,aswellasassessoperativeoutcomes.
