Intraocular pressure - Wikipedia

Intraocular pressure (IOP) is the fluid pressure inside the eye. Tonometry is the method eye care professionals use to determine this. Intraocularpressure FromWikipedia,thefreeencyclopedia Jumptonavigation Jumptosearch Fluidpressureinsidetheeye Apatientinfrontofatonometer Intraocularpressure(IOP)isthefluidpressureinsidetheeye.Tonometryisthemethodeyecareprofessionalsusetodeterminethis.IOPisanimportantaspectintheevaluationofpatientsatriskofglaucoma.[1]Mosttonometersarecalibratedtomeasurepressureinmillimetersofmercury(mmHg). Contents 1Physiology 2Measurement 3Classification 4Influencingfactors 4.1Dailyvariation 4.2Fitnessandexercise 4.3Musicalinstruments 4.4Drugs 5Significance 6References 7Externallinks Physiology[edit] Intraocularpressureisdeterminedbytheproductionanddrainageofaqueoushumourbytheciliarybodyanditsdrainageviathetrabecularmeshworkanduveoscleraloutflow.Thereasonforthisisbecausethevitreoushumourintheposteriorsegmenthasarelativelyfixedvolumeandthusdoesnotaffectintraocularpressureregulation. Animportantquantitativerelationship(Goldmann'sequation)isasfollows:[2] P o = F − U C + P v {\displaystyleP_{o}={\frac{F-U}{C}}+P_{v}} Where: P o {\displaystyleP_{o}} istheIOPinmillimetersofmercury(mmHg) F {\displaystyleF} therateofaqueoushumourformationinmicrolitersperminute(μL/min) U {\displaystyleU} theresorptionofaqueoushumourthroughtheuveoscleralroute(μL/min) C {\displaystyleC} isthefacilityofoutflowinmicrolitersperminutepermillimeterofmercury(μL/min/mmHg) P v {\displaystyleP_{v}} theepiscleralvenouspressureinmillimetersofmercury(mmHg). TheabovefactorsarethosethatdriveIOP. Measurement[edit] Diatontranspalpebraltonometer Palpationisoneoftheoldest,simplest,andleastexpensivemethodsforapproximateIOPmeasurement.[3]Intraocularpressureismeasuredwithatonometeraspartofacomprehensiveeyeexamination. Measuredvaluesofintraocularpressureareinfluencedbycornealthicknessandrigidity.[4][5]Asaresult,someformsofrefractivesurgery(suchasphotorefractivekeratectomy)cancausetraditionalintraocularpressuremeasurementstoappearnormalwheninfactthepressuremaybeabnormallyhigh.Anewertranspalpebralandtransscleraltonometrymethodisnotinfluencedbycornealbiomechanicsanddoesnotneedtobeadjustedforcornealirregularitiesasmeasurementisdoneoveruppereyelidandsclera.[6] Classification[edit] Currentconsensusamongophthalmologistsandoptometristsdefinesnormalintraocularpressureasthatbetween10mmHgand20mmHg.[7][8][9][10]Theaveragevalueofintraocularpressureis15.5mmHgwithfluctuationsofabout2.75mmHg.[11] Ocularhypertension(OHT)isdefinedbyintraocularpressurebeinghigherthannormal,intheabsenceofopticnervedamageorvisualfieldloss.[12][13] Ocularhypotension,hypotony,orocularhypotony,istypicallydefinedasintraocularpressureequaltoorlessthan5mmHg.[14][15]Suchlowintraocularpressurecouldindicatefluidleakageanddeflationoftheeyeball. Influencingfactors[edit] Dailyvariation[edit] Intraocularpressurevariesthroughoutthenightandday.Thediurnalvariationfornormaleyesisbetween3and6mmHgandthevariationmayincreaseinglaucomatouseyes.Duringthenight,intraocularpressuremaynotdecrease[16]despitetheslowerproductionofaqueoushumour.[17]Glaucomapatients'24-hourIOPprofilesmaydifferfromthoseofhealthyindividuals.[18] Fitnessandexercise[edit] ThereissomeinconclusiveresearchthatindicatesthatexercisecouldpossiblyaffectIOP(somepositivelyandsomenegatively).[19][20][12] Musicalinstruments[edit] Playingsomemusicalwindinstrumentshasbeenlinkedtoincreasesinintraocularpressure.A2011studyfocusedonbrassandwoodwindinstrumentsobserved"temporaryandsometimesdramaticelevationsandfluctuationsinIOP".[21] Anotherstudyfoundthatthemagnitudeofincreaseinintraocularpressurecorrelateswiththeintraoralresistanceassociatedwiththeinstrument,andlinkedintermittentelevationofintraocularpressurefromplayinghigh-resistancewindinstrumentstoincidenceofvisualfieldloss.[22] Therangeofintraoralpressureinvolvedinvariousclassesofethnicwindinstruments,suchasNativeAmericanflutes,hasbeenshowntobegenerallylowerthanWesternclassicalwindinstruments.[23] Drugs[edit] Intraocularpressurealsovarieswithanumberofotherfactorssuchasheartrate,respiration,fluidintake,systemicmedicationandtopicaldrugs.Alcoholandmarijuanaconsumptionleadstoatransientdecreaseinintraocularpressureandcaffeinemayincreaseintraocularpressure.[24] Takenorally,glycerol(oftenmixedwithfruitjuicetoreduceitssweettaste)cancausearapid,temporarydecreaseinintraocularpressure.Thiscanbeausefulinitialemergencytreatmentofseverelyelevatedpressure.[25] Thedepolarisingmusclerelaxantsuccinylcholine,whichisusedinanaesthesia,transientlyincreasesIOPbyaround10 mmHgforafewminutes.Thisissignificantforexampleifthepatientrequiresanaesthesiaforatraumaandhassustainedaneye(globe)perforation.Themechanismisnotclearbutitisthoughttoinvolvecontractionoftonicmyofibrilsandtransientdilationofchoroidalbloodvessels.KetaminealsoincreasesIOP.[26] Significance[edit] Ocularhypertensionisthemostimportantriskfactorforglaucoma. Intraocularpressurehasbeenmeasuredasasecondaryoutcomeinasystematicreviewcomparingtheeffectofneuroprotectiveagentsinslowingtheprogressionofopenangleglaucoma.[27] Differencesinpressurebetweenthetwoeyesareoftenclinicallysignificant,andpotentiallyassociatedwithcertaintypesofglaucoma,aswellasiritisorretinaldetachment. Intraocularpressuremaybecomeelevatedduetoanatomicalproblems,inflammationoftheeye,geneticfactors,orasaside-effectfrommedication.Intraocularpressurelawsfollowfundamentallyfromphysics.Anykindsofintraocularsurgeryshouldbedonebyconsideringtheintraocularpressurefluctuation.Suddenincreaseofintraocularpressurecanleadtointraocularmicrobarotraumaandcauseischemiceffectsandmechanicalstresstoretinalnervefiberlayer.Suddenintraocularpressuredropcanleadtointraoculardecompressionthatgeneratesmicrobubblesthatpotentiallycausemultiplemicroemboliandleadingtohypoxia,ischemiaandretinalmicrostructuredamage.[28] References[edit] ^Farandos,NicholasM.;Yetisen,AliK.;Monteiro,MichaelJ.;Lowe,ChristopherR.;Yun,SeokHyun(April2015)."Contactlenssensorsinoculardiagnostics".AdvancedHealthcareMaterials.4(6):792–810.doi:10.1002/adhm.201400504.PMID 25400274.S2CID 35508652. ^AptelF,WeinrebRN,ChiquetC,MansouriK(November2016)."24-hmonitoringdevicesandnyctohemeralrhythmsofintraocularpressure".ProgRetinEyeRes.55:108–148.doi:10.1016/j.preteyeres.2016.07.002.PMID 27477112.S2CID 24677841. ^Heidary,Fatemeh;Gharebaghi,Reza;Heidary,Roghayeh(30July2010)."Palpationbyblindexaminers:Anovelapproachforglaucomascreening".ClinicalOphthalmology(Auckland,N.Z.).4:671–672.doi:10.2147/opth.s11167.ISSN 1177-5483.PMC 2915851.PMID 20689781. ^GrieshaberMC,SchoetzauA,ZawinkaC,FlammerJ,OrgulS(June2007)."EffectofcentralcornealthicknessondynamiccontourtonometryandGoldmannapplanationtonometryinprimaryopen-angleglaucoma".Arch.Ophthalmol.125(6):740–4.doi:10.1001/archopht.125.6.740.PMID 17562982. ^TanakaGH(April1998)."Cornealpachymetry:aprerequisiteforapplanationtonometry?".Arch.Ophthalmol.116(4):544–5.PMID 9565063. ^CachoI,Sanchez-NavesJ,BatresL,PintorJ,CarracedoG(2015)."ComparisonofIntraocularPressurebeforeandafterLaserInSituKeratomileusisRefractiveSurgeryMeasuredwithPerkinsTonometry,NoncontactTonometry,andTranspalpebralTonometry".JOphthalmol.2015:683895.doi:10.1155/2015/683895.PMC 4475733.PMID 26167293. ^webMD-Tonometry ^GlaucomaOverviewArchived4July2008attheWaybackMachinefromeMedicine ^HashemiH,KashiAH,FotouhiA,MohammadK(June2005)."DistributionofintraocularpressureinhealthyIranianindividuals:theTehranEyeStudy".BrJOphthalmol.89(6):652–7.doi:10.1136/bjo.2004.058057.PMC 1772663.PMID 15923494. ^Pooranee(9October2015)."DoyouknowaboutIntraOcularPressure?".HealthEducationBureau,InformationandCommunicationTechnologyAgency,SriLanka.Retrieved4November2015. ^JanuntsE."Opticalremotesensingofintraocularpressurebyanimplantablenanostructuredarray".MedizinischeFakultätderUniversitätdesSaarlandes.Archivedfromtheoriginalon25April2012. ^abVieiraGM,OliveiraHB,deAndradeDT,BottaroM,RitchR(September2006)."Intraocularpressurevariationduringweightlifting".Arch.Ophthalmol.124(9):1251–4.doi:10.1001/archopht.124.9.1251.PMID 16966619. ^OcularHypertension,AmericanOptometricAssociation.Accessed2015-11-3. ^"OcularHypotony:Background,Pathophysiology,Epidemiology".MedscapeReference.5February2014.Retrieved4November2015. ^HendererJD,BudenzDL,FlynnHW,SchiffmanJC,FeuerWJ,MurrayTG(February1999)."Elevatedintraocularpressureandhypotonyfollowingsiliconeoilretinaltamponadeforcomplexretinaldetachment:incidenceandriskfactors".Arch.Ophthalmol.117(2):189–95.doi:10.1001/archopht.117.2.189.PMID 10037563. ^LiuJH,WeinrebRN(May2011)."Monitoringintraocularpressurefor24h".BrJOphthalmol.95(5):599–600.doi:10.1136/bjo.2010.199737.PMID 21330554.S2CID 42736853. ^BrubakerRF(1991)."Flowofaqueoushumorinhumans".InvestOphthalmolVisSci.32(13):3145–3166.PMID 1748546. ^LiuJH,ZhangX,KripkeDF,WeinrebRN(April2003)."Twenty-four-hourintraocularpressurepatternassociatedwithearlyglaucomatouschanges".Invest.Ophthalmol.Vis.Sci.44(4):1586–90.doi:10.1167/iovs.02-0666.ISSN 1552-5783.PMID 12657596. ^Studieshavealsobeenconductedonbothhealthyandsedentaryindividualstodetermineifintraocularpressurecouldbereducedwithothertypesofexercise.Someformsofexertionhavebeenfoundtoresultinadecreaseinintraocularpressure.Exercisesstudiedincluded;walking,jogging,andrunning.AcuteDynamicExerciseReducesIntraocularPressureArchived28September2011attheWaybackMachine,DepartmentsofOphthalmology,Physiology,FacultyofMedicine,AtatürkUniversity,Erzurum-Turkey.July1999. ^QureshiIA.Effectsofmild,moderateandsevereexerciseonintraocularpressureofsedentarysubjects.RawalpindiMedicalCollege,Rawalpindi,Pakistan ^SchmidtmannG,JahnkeS,SeidelEJ,SickenbergerW,GreinHJ(June2011)."Intraocularpressurefluctuationsinprofessionalbrassandwoodwindmusiciansduringcommonplayingconditions"(PDF).GraefesArch.Clin.Exp.Ophthalmol.249(6):895–901.doi:10.1007/s00417-010-1600-x.hdl:10026.1/10195.PMID 21234587.S2CID 21452109. ^SchumanJS,MassicotteEC,ConnollyS,HertzmarkE,MukherjiB,KunenMZ(January2000)."Increasedintraocularpressureandvisualfielddefectsinhighresistancewindinstrumentplayers".Ophthalmology.107(1):127–33.doi:10.1016/s0161-6420(99)00015-9.PMID 10647731. ^ ClintonF.Goss(August2013)."IntraoralPressureinEthnicWindInstruments"(PDF).Flutopedia.arXiv:1308.5214.Bibcode:2013arXiv1308.5214G.Retrieved22August2013. ^IntraocularpressuremeasureonnormaleyesbyPardiantoGetal.,inMimbarIlmiahOftalmologiIndonesia.2005;2:78-9. ^DranceSM(October1964)."EffectofOralGlycerolonIntraocularPressureinNormalandGlaucomatousEyes".Arch.Ophthalmol.72(4):491–3.doi:10.1001/archopht.1964.00970020491009.PMID 14184494. ^BruntonL,ChabnerBA,KnollmanB(2011)."19.GeneralAnestheticsandTherapeuticGases".Goodman&Gilman's:ThePharmacologicalBasisofTherapeutics(12th ed.).NewYork,USA:TheMcGraw-HillCompanies,Inc.p. 539.ISBN 978-0-07-162442-8. ^SenaDF,LindsleyK(January2017)."Neuroprotectionfortreatmentofglaucomainadults".CochraneDatabaseSystRev.1:CD006539.doi:10.1002/14651858.CD006539.pub4.PMC 5370094.PMID 28122126. ^PardiantoG(March2015)."Recentawarenessandconsiderationofintraocularpressurefluctuationduringeyesurgery".JCataractRefractSurg.41(3):695.doi:10.1016/j.jcrs.2015.01.009.PMID 25804599. Externallinks[edit] www.allaboutvision.comWhatToExpectDuringaComprehensiveEyeExam www.emedicinehealth.comOcularHypertension www.tonometerdiaton.comTranspalpebralTransscleralTonometry vtePhysiologyofthevisualsystemVision Accommodation Gaze Intraocularpressure Visualfield Colorvision Colorblindness Achromatopsia Köllner'srule Opponentprocess Dichromacy Monochromacy Pentachromacy Tetrachromacy Trichromacy Authoritycontrol:Nationallibraries France(data) Germany Israel UnitedStates Japan CzechRepublic Retrievedfrom"https://en.wikipedia.org/w/index.php?title=Intraocular_pressure&oldid=1092619429" Categories:OphthalmologyEyeVisionHiddencategories:WebarchivetemplatewaybacklinksArticleswithshortdescriptionShortdescriptionmatchesWikidataArticleswithBNFidentifiersArticleswithGNDidentifiersArticleswithJ9UidentifiersArticleswithLCCNidentifiersArticleswithNDLidentifiersArticleswithNKCidentifiersUsedmydatesfromAugust2019 Navigationmenu Personaltools NotloggedinTalkContributionsCreateaccountLogin Namespaces ArticleTalk English Views ReadEditViewhistory More Search Navigation MainpageContentsCurrenteventsRandomarticleAboutWikipediaContactusDonate Contribute HelpLearntoeditCommunityportalRecentchangesUploadfile Tools WhatlinkshereRelatedchangesUploadfileSpecialpagesPermanentlinkPageinformationCitethispageWikidataitem Print/export DownloadasPDFPrintableversion Languages العربيةBosanskiCatalàČeštinaDeutschEspañolفارسیFrançais한국어HrvatskiItalianoעבריתമലയാളംNederlands日本語NorskbokmålPolskiPortuguêsРусскийSuomiSvenskaУкраїнська中文 Editlinks