Mechanism of Action of Selective Laser Trabeculoplasty and Predictors of ResponseMechanism of Action of SLT

摘要

Purpose:Thisstudywasdesignedtoevaluatethechangesinaqueoushumordynamics(AHD)producedbyselectivelasertrabeculoplasty(SLT)andtoexploreifbaselineAHDparametersarepredictiveofIOPresponsetoSLT.Methods:Thirty-oneconsecutivesubjectsdiagnosedwithocularhypertensionorprimaryopen-angleglaucomascheduledtoundergoSLTastheirprimaryIOP-loweringtherapywereenrolledinthisprospectiveobservationalstudy.SubjectsunderwentbaselineassessmentofAHDinbotheyes.VariablesassessedwereIOPsat9AMandnoon,aqueoushumorflowrate(fluorophotometry),episcleralvenouspressure(EVP,venomanometry),outflowfacility(pneumatonographyandfluorophotometry)anduveoscleraloutflow(calculatedusingmodifiedGoldmannequation).Allsubjectsunderwent360degreesSLTandAHDmeasurementswererepeated3monthslater.Results:Comparedwithbaseline,IOPsafterSLTweresignificantlylowerat9AM(22.9?±5.1vs.19.7?±3.0mmHg;P=0.001)andnoon(23.4?±4.6vs.20.0?±3.5mmHg;P0.001).Outflowfacilitybyfluorophotometrywassignificantlyincreasedfrom0.17?±0.11??L/min/mmHgatbaselineto0.24?±0.14??L/min/mmHgat3months(P=0.008).Outflowfacilitybytonography(baseline:0.16?±0.07??L/min/mmHgvs.3months:0.22?±0.16??L/min/mmHg;P=0.046)wassimilarlyincreased.NochangeinaqueousfloworEVPwasobserved.TherewerenochangesinIOPorAHDinthecontralateraluntreatedeye.Usingmultiplelinearregressionmodels,higherbaselineaqueousflow,lowerbaselineoutflowfacility,andpossiblyloweruvescleraloutflowwereassociatedwithmoreIOPloweringwithSLT.Conclusions:TheIOP-loweringeffectofSLTismediatedthroughanincreaseinoutflowfacility.Thereisnocontralateraleffect.HigheraqueousflowandloweroutflowfacilitymaybepredictiveofbetterresponsetoSLT.