第1页共10页编号：时间：2021年x月x日书山有路勤为径，学海无涯苦作舟页码：第1页共10页ComparisonbetweengraticuleandimagecaptureassessmentoflowertearfilmmeniscusheightJ.Santodomingo-Rubido,a,,J.S.WolffsohnaandB.GilmartinaaOphthalmicResearchGroup,SchoolofLifeandHealthSciences,AstonUniversity,Birmingham,UKAvailableonline14July2006.AbstractPurposeTocomparegraticuleandimagecaptureassessmentofthelowertearfilmmeniscusheight(TMH).MethodsLowertearfilmmeniscusheightmeasuresweretakenintherighteyesof55healthysubjectsattwostudyvisitsseparatedby6months.TwoimagesoftheTMHwerecapturedineachsubjectwithadigitalcameraattachedtoaslit-lampbiomicroscopeandstoredinacomputerforfutureanalysis.Usingthebestoftwoimages,theTMHwasquantifiedbymanuallydrawingalineacrossthetearmeniscusprofile,followingwhichtheTMHwasmeasuredinpixelsandconvertedintomillimetres,whereonepixelcorrespondedto0.0018mm.Additionally,graticulemeasureswerecarriedoutbydirectobservationusingacalibratedgraticuleinsertedintothesameslit-lampeyepiece.Thegraticulewascalibratedsothatactualreadings,in0.03mmincrements,couldbemadewitha40×ocular.ResultsSmallervaluesofTMHwerefoundinthisstudycomparedtopreviousstudies.TMH,asmeasuredwiththeimagecapturetechnique(0.13±0.04mm),wassignificantlygreater(byapproximately0.01±0.05mm,p=0.03)thanthatmeasuredwiththegraticuletechnique(0.12±0.05mm).Nobiaswasfoundacrosstherangesampled.RepeatabilityoftheTMHmeasurementstakenattwostudyvisitsshowedthatgraticulemeasuresweresignificantlydifferent(0.02±0.05mm,p=0.01)andhighlycorrelated(r=0.52,p<0.0001),whereasimagecapturemeasuresweresimilar(0.01±0.03mm,p=0.16),andalsohighlycorrelated(r=0.56,p<0.0001).ConclusionsAlthoughgraticuleandimageanalysistechniquesshowedsimilarmeanvaluesforTMH,theimagecapturetechniquewasmorerepeatablethanthegraticuletechniqueandthiscanbe第2页共10页第1页共10页编号：时间：2021年x月x日书山有路勤为径，学海无涯苦作舟页码：第2页共10页attributedtothehighermeasurementresolutionoftheimagecapture(i.e.0.0018mm)comparedtothegraticuletechnique(i.e.0.03mm).Keywords:Tearmeniscusheight;Tearprism;Tearfilm;RepeatabilityArticleOutline1.Introduction2.Methods2.1.Statisticalanalysis3.Results4.DiscussionAcknowledgementsReferences1.IntroductionThetearmeniscus,whichisformedbetweenthelidsurfaceandthebulbarconjunctiva,ispresentalongthesuperiorandinferiorlidmargins.Ithasbeenestimatedthatthetearmeniscusholds75–90%ofthetotalvolumeofthetearfilm[1].Therefore,carefulexaminationofthelowerlidtearmeniscusheight(TMH)islikelytoprovideasimplebutclinicallyusefulindicationoftearvolume.AssessmentoftheTMHiscommonlyusedbyeyecarepractitionersuniversallyaspartofroutineocularassessments[2]and[3].However,meanabsolutevaluesofTMHinnormaleyeshavebeenreportedtovarybetween0.14and0.46mmdependingonthetechniqueemployed[4],[5],[6],[7],[8],[9],[10],[11],[12],[13],[14],[15],[16],[17],[18],[19]and[20].Studiesusingcalibratedgraticulesinsertedintotheslit-lampeyepiecehavereportedmeanvalueswhichvarybetween0.15and0.35mminnormalhealthyeyes(Table1)[4],[5],[6],[7],[8]and[9].Anotherstudyhasusedthecalibratedvariableslitbeamheightofaslit-lamptomeasuretheTMHandreportedameanvalueof0.32mm[10].VideocapturetechniquesmeasuretheTMHbytakinganimageofthemeniscusinwhichtheupperandlowerextentofthetearmeniscusislocatedsubjectively(oftenbydrawingaline)andthen,usingcomputersoftware,convertthenumberofpixelsbetweenthesepointstoap...
