MNREADApp

Continuous-textreading-acuitytestfornormalandlowvision

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UserGuide

Version0.9

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CopyrightUniversityofMinnesota

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TableofContents

1. Symbols&Terminology.............................................................................................................3

2. Copyright..........................................................................................................................................33. Overview..........................................................................................................................................43.1 Testingprocedure................................................................................................................................53.2 Testdesign..............................................................................................................................................53.2.1 Testsentences...................................................................................................................................................53.2.2 Printsizes............................................................................................................................................................53.2.3 Font ......................................................................................................................................................................6

3.3 Devicerequirements...........................................................................................................................64. Gettingstarted...............................................................................................................................6

4.1.1 SettinguptheiPad..........................................................................................................................................64.1.2 Launchingtheapp...........................................................................................................................................6

5. Runninga‘practice’test.............................................................................................................8

6. RunningatestwithSavedData................................................................................................87. Interpretingtheresults...........................................................................................................117.1 AutomaticestimationoftheMNREADparameters................................................................117.2 ManualestimationoftheMNREADparameters.....................................................................127.3 Datastorage........................................................................................................................................137.4 Datasharingandretrieving...........................................................................................................137.5 Startinganewtest.............................................................................................................................14

8. Settings..........................................................................................................................................148.1 Viewingdistance................................................................................................................................158.2 Contrastpolarity................................................................................................................................158.3 Language..............................................................................................................................................158.4 Externalkeyboard.............................................................................................................................168.5 Operatoremail...................................................................................................................................178.6 Sizeunit................................................................................................................................................17

9. LightingConditions&Brightness.........................................................................................1910. Appendix....................................................................................................................................2010.1 ConversiontablebetweenlogMARandSnellenacuityunits...........................................2010.2 ConversiontablebetweenlogMAR,fontsizeandMunits................................................21

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1. Symbols&TerminologyThisuserguideusestheterms:

• ExperimenterorUsertorefertothepersonoperatingtheiPad®device;• PatientorSubjecttorefertothepersonundergoingthetest.

Thismanualusesthefollowingsymbolstoindicatespecialinformation:

2. CopyrightMembersofthedevelopmentteamincludeAurelieCalabrese,LongTo,GordonE.Legge,J.StephenMansfield,ChuckBigelowandMichaelCrossland.HereishowtocitetheMNREADappinpublications:Calabrese,A.,GamamS.,MansfieldJ.S.,LeggeG.E.ImplementingtheMNREADReadingAcuityTestonaniPad3.InvestOphthalmol.Vis.Sci.2014;55(13):5601.Forquestions,pleasecontactDr.Calabreseatacalabre@umn.eduTheMNREADappusestheproprietaryfontTimesLTRoman,Version6.04,propertyofHeidelbergerDruckmaschinenAGandexclusivelylicensedthroughLinotypeLibraryGmbH.Thesamefonttypesetisusedintheprintedchart.EnglishandSpanishversionsoftheMNREADchartsareavailablefrom:

Precision Vision, Inc. 1725 Killkenny Court, Woodstock, IL 60098, USA Phone: +1-815-223-2022 Fax: +1-815-223-2224 www.precision-vision.com

MNREADiscopyrightprotectedbytheUniversityofMinnesota.

Tipsthathelpyoubetterusethisapp.

ImportantinformationpertainingtoMNREADtesting.

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3. OverviewTheMNREADappisadigitalversionoftheprintedMNREADACUITYCHARTS,acontinuous-textreading-acuitytestsuitableformeasuringthereadingacuityandreadingspeedofnormalandlow-visionpatients.ThistestwasdevelopedattheMinnesotaLaboratoryforLow-VisionResearch,UniversityofMinnesota,Minneapolis,Minnesota,USA,inresearchfundedbytheNationalInstitutesofHealth.

TheMNREADappisdesignedtorunonaniPad(3rdgenerationorabove)andfeaturesthefollowingfunctions:

• Sentencedisplay;• Readingtimerecording;• MNREADcurvefitting;• MNREADparametersestimation;• Datarecordingandexport;• Practicetest.

TheMNREADappcontainsseveralversionsofthetestwithdifferenttestsentences.Eachoftheseversionsisavailablewitheitherblack-on-white(regularcontrast)orwhite-on-black(reversecontrast).

TheMNREADappcanbeusedtomeasure:

• READINGACUITY -Thesmallestprintthatthepatientcanreadwithoutmakingsignificanterrors;

• CRITICALPRINTSIZE-Thesmallestprintthatthepatientcanreadwithmaximumspeed;

• MAXIMUMREADINGSPEED-Thepatient’sreadingspeedwhenreadingisnotlimitedbyprintsize;

• READINGACCESSIBILITYINDEX-Thepatient’saveragereadingspeedmeasuredoverthe10largestprintsizesontheMNREADacuitychart,normalizedbythemeanvalueforagroupofnormallysightedyoungadults.Thissingle-valuedmeasurerepresentsthepatient’svisualaccesstocommonlyencounteredprintedmaterial.

• ClickherefordetailedinstructionsoftheprintedMNREADcharts.

• ClickhereforgeneralinformationabouttheprintedMNREADcharts.

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3.1 Testingprocedure1. Thesentencesarepresentedfromthelargesttosmallestprint.Patientsshouldread

thetestsentencesaloud,startingeitherfromthefirstsentence(largestprint)orfromseveralstepsabovetheirpreviouslyrecordedletteracuity.NotethatdisplayingthefullrangeofsentencesisrecommendedinordertogetacorrectestimationoftheReadingAccessibilityIndex.

2. Instructpatientstoreadthesentencesasquicklyandaccuratelyaspossible.3. Patientsshouldcontinuereadingthesmallersizesuntiltheycannotreadanywords

inasentence.4. Encouragepatientstoguessevenwhentheybelievethewordsareunreadable.

3.2 Testdesign

3.2.1 TestsentencesTheMNREADsentencesprovidesamplesofreadingmaterialdesignedtodemandthevisualprocessingcapabilitiesandeye-movementcontrolrequiredfornormaltextreading.Eachsentencecontains60characters(includingspacesbetweenwordsandattheendofeachline)printedasthreelineswithevenleftandrightmargins.Thevocabularyusedinthesentencesisselectedfromwordsappearingwithhighfrequencyin2ndand3rdgradereadingmaterial.

3.2.2 PrintsizesEachtestcontainsaseriesof14sentenceswithprintdecreasinginsizeby0.1logunit.Notethatthenumberofsentencesisreducedfromtheprintedversion,duetoscreensizeandresolutionlimitations.

Thephysicalprintsizesrangefrom6.3Mto0.32M(inSloanMnotation)or9.3mmto0.5mm(inx-height).Fromtherecommendedviewingdistanceof40cm(16inches)thecorrespondingangularprintsizerangesfrom1.2to–0.1logMAR(Snellenequivalents20/320to20/16).Thisrangecanbeextendedbyusingashorterorlongerviewingdistance(seesection8.1).

Eachsentenceis0.1logMARunitssmallerthantheprevioussentence(i.e.,about80%ofthesize).Logarithmicscalingallowseasycalculationofreadingacuityatnon-standardviewingdistances,asmightberequiredforlow-visionpatientswithlogMARacuitygreaterthan1.2,orforpatientswhoseactivitiesrequirecorrectiontospecificdistances.

• Printsizeismeasuredastheheightofalower-case‘x’.

• LogMARprintsizeiscalculatedasfollows:log10[(anglesubtendedbyx-height)/(5arcmin)]

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3.2.3 Font SentencesaredisplayedinTimesRoman,aproportionallyspacedfont,similartothatfoundinmanynewspapersandbooks.Thetextisrenderedwithhighcontrast.

3.3 DevicerequirementsTheMNREADappisdesignedforiPaduse,withthefollowingrequirements:

• iPad3rdgenerationorabove• 9.7-inch(diagonal)retinadisplay• 2048-by-1536resolutionat264pixelsperinch(ppi)• iOS7.0orabove

4. Gettingstarted4.1.1 SettinguptheiPadTheiPadshouldbeplacedatawell-illuminatedlocationthatdoesnotproducescreenreflectionsvisibletothepatient.BecauseoftheveryglossynatureoftheiPadscreen,itisrecommendedtoinstallanantiglarescreenprotector.Keephandyacleaningclothtoremovefingerprintsorsmudgesfromthescreen.Ideally,theiPadshouldbemountedonastandperpendiculartothepatient’slineofsighttopresentthesentencesateyelevelandavoidglareorreflection.TheexaminershouldsitnexttothepatientandoperatetheiPadbyeithertouchingthescreenorusinganexternalBluetoothkeyboardconnectedtotheiPad(seesection8.4formoredetailsaboutthekeyboardoption).Makesuretochooseaviewingdistancetocoverthepatient’slegiblerangeofprintsizes(seesection8.1).Beforestartingthetest,measurethisdistancefromthepatient’seyestothecenterofthescreen.Throughoutthetest,makesurethatthepatientmaintainsthechosendistanceanddoesnotmoveforward.

4.1.2 Launchingtheapp

TostartusingtheMNREADapp,tapitsicon.Theappopensonthehomescreen.

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• Tosetthetestparameters(language,contrastpolarity,viewingdistance,…)clickon“SETTINGS”(seeSection8foradetailedlistofparametersandhowtosetthemup);

• Clickonthe“Notes”boxtoenterandsavenotesaboutthetest(e.g.,eyetested,…);• Enterthesubjectidentifierintothe“Patient/ParticipantID”field;• Ifthetestingdistanceisdifferentfromthedefaultvalueof40cm(16inches),

modifytheviewingdistancebyclickingonthe‘+’or‘-‘buttons,orbyaccessingthegeneralsettingsbyclickingon“SETTINGS”;

• Selectachartnumber(thenumberofavailablechartswillchangedependingonthelanguageselected);

• Torunapracticetest,clickon“PRACTICE”;• Torunarealtest,clickon“START”.

BelowarethedefaultsettingsoftheMNREADtest:

• Language:• Polarity:• Viewingdistance:

EnglishNormal(‘black-on-white’)40cm(16inches)

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5. Runninga‘practice’testTofamiliarizeasubjectwiththetask,itispossibletorunapracticetestbyclickingon“PRACTICE”fromtheHomeScreen.Sentenceswillbedisplayedasforarecordedtest,butnodatawillbesaved.Thesamplesentencesareshowninthefirst5largestprintsizesofarealtest.Thesentencesdisplayedduringapracticetestwon’tbeshownagainduringarecordedtest.

6. RunningatestwithSavedDataFromtheHomescreen,clickon“START”tobeginrunningtheMNREADtest.Eachsentenceisprecededbya‘preparation’screenshowingthepositionoftheupcomingsentence.Thebottomlineofthepreparationscreenprovidesinformationaboutthetestandthesentencetocome:

• Thechartnumber;• Thesentencenumber;• Theangularprintsizeadjustedfortheviewingdistance(logMAR,Snellenor

Decimal);• Thephysicalprintsize(MorPointunits):• Theviewingdistance.

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Todisplaythefirstsentence,clickon“GO”,orhitthekeyboardspacebar.Makesurethatthesubjectisreadytostartreadingbeforeyoulaunchthetrial.

Insomecases,theexaminermaywanttoskiponeorseveraltrials,eithertosavetime,orbecausethepatientcannotreadlargeprint(forexample,inpresenceofaringscotoma).Toskiptheupcomingtrialandgodirectlytothenextsentence,clickthebutton“SKIP”.Nodatawillberecorded.Clickingon“GO”launchesthefirsttrialandthefirstsentenceappearsonthescreen.Thesubjectshouldstartreadingoutloudandasfastaspossibleassoonasthesentenceappearsonthescreen.Oncethesubjecthasfinishedreadingthesentence,theusercanterminatethetrialandstopthetimerbyclickingontherightpartofthescreen,oronthekeyboardspacebar(notethattapswithinthefirstsecondofatrialarenotacceptedtoavoidusermistap).Thetime(inseconds)isrecordedautomaticallybytheapp.

Insomecases,thesubjectmaywanttotriggerthetrialshim/herselfbyclickingthe“Go”button.Thisshowstheadvantageofengaginghim/herintothetest.Nevertheless,weadvicetheusertoremaininchargeofendingeachtrialinordertoavoiddelaysandimprovetimerecordingconsistency.

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Onceatrialhasbeenstopped,thescorescreenappears.Itshows:

• Thesentencejustdisplayedtohelptheusercounterrorsmadeduringreading;• An‘Errorcount’columnwithbuttonsfrom0(default)to10(ormore).Recordthe

numberoferrorsmadeduringthetrialbyclickingonthecorrespondingbutton.Inaddition,onecanusethe“Unabletoread”buttonthatsetstheerrorcountto10;

• Thereadingtime(inseconds);• A‘STOP’buttontoterminatethetestinganddisplaythefinalscorescreen

containingaplotoftheMNREADdata;• An“IGNORE”buttononecanclicktoignorethedatafromthepresenttrial.This

optioncanbeusedforexample,ifthesubjectgotdistractedduringthereading,oriftheexperimenterstoppedthetrialtooearlybyclickingonthescreenbymistake;

• A‘CONTINUE’buttontogotothePreparationScreenforthenextsentence.

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7. InterpretingtheresultsOncethetestiscomplete,eitherbecauseallthesentenceshavebeendisplayed,orbecausetheuserterminatedthetest,thefinalscorescreenisdisplayed.ThereadingspeedisplottedasafunctionofprintsizeaccordingtothegeneralMNREADgraphingprocedure.Eachdatapointrepresentsasentencewiththenumberofmisreadwordsdisplayedaboveit(onlywhendifferentfrom0).Printsizeisshownboth:

• inangularunitsonthebottomx-axis(LogMAR,SnellenorDecimal)and• inphysicalunitsonthetopx-axis(MorPoint).

Anynon-standardviewingdistances(ie.differentfrom40cm)aretakenintoaccountbytheangularprintsizescales.

7.1 AutomaticestimationoftheMNREADparametersMaximumReadingSpeedandCriticalPrintSizeareestimatedautomaticallybytheappandshownontheplot(seetheInformationBoxbelowfordetailsabouttheautomaticparameterestimation).TheReadingAcuity(RA)andReadingAccessibilityIndex(ACC)arealsocalculatedbytheappanddisplayedontheplot.Notethatinordertoestimatethesetwovaluesreliably,thetesthastocontinueuntilNOWORDCANBEREADACCURATELYbythesubject.

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Valuesofallfourparametersarestoredinthedataspreadsheetsavedattheendofeachtest(seesection7.3).

7.2 ManualestimationoftheMNREADparametersIncasethealgorithmicestimationdoesnotprovideagoodfit(seeFiguresbelow),theusercanover-writethecomputationandperformamanualestimation.Afterclickingon“MANUAL”atthebottomleftofthescreen,adouble-taponthescreenwillre-positionthedashedcrosshairtothechosen“tap”positionandoverwritetheautomaticestimationoftheMaximumReadingSpeedandCriticalPrintSize.Theestimationcanberefinedbydraggingthecrosshairwithonefinger.

• TheCriticalPrintSizeisdefinedastheprintsizeatwhichsubsequentsmallerprintsizeswerereadat1.96SDslowerthanthemeanoftheprecedingprintsizes.

• TheMaximumReadingSpeedisestimatedasthemeanreadingspeedforsentencesinprintlargerthantheCriticalPrintSize.

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7.3 DatastorageForeachtestrun,thedataaresavedandstoredintheinternalmemoryoftheiPadwithintwodifferentfiles:

1. AnimageoftheMNREADcurve(.pngformat)2. Adataspreadsheet(.csvformat)including:

• Settingsusedduringthetest(polarity,viewingdistance,etc.);• ThefourMNREADparameters(MaximumReadingSpeed,CriticalPrintSize,

ReadingAcuityandReadingAccessibilityIndex)• Individualdataforeachsentenceread(readingtime,error,etc.)

7.4 DatasharingandretrievingAttheendofatest,onecansharethecurrentresultsviaemail.Fromthefinalscorescreen,clickthe“EMAIL”buttontosendbothdatafiles(curveandspreadsheet)totherecipientofyourchoice.Ifthesameemailaddressisusedfrequently,onecansetupadefaultaddressintheSettings(seesection8)OnecanalsoretrieveresultsfromprevioustestsviaiTunesbyfollowingthesesteps:1. ConnecttheiPadtoyourcomputerandaccessitsinfothroughiTunes;2. AccesstheAppstabofyouriPadintheleftpaneloftheiTuneswindow;3. Scrolldownthemainpaneltoaccessthe“FileSharing”section;

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4. Intheleftpanel,selecttheMNREADapp.;5. Intherightpanelthereisalistoffolders,eachonecorrespondingtoaMNREADtest;6. Selectthefoldersofinterestandclick“Saveto”tostorethedataonyourcomputer.

7.5 StartinganewtestFromthescorescreen,clickonthebutton“NEWTEST”.

8. SettingsToconfigurethesettingsoftheMNREADtest(viewingdistance,polarity,etc.),clickonthebutton“SETTINGS”fromthehomescreen.

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8.1 ViewingdistanceThestandardviewingdistancetoruntheMNREADtestis40cm(16inches).However,tocompensateforthesmallernumberofprintsizesthatcanbeaccuratelydisplayedontheiPad,therangeofprintsizescanbeextended:

• Tolargerangularvaluesbytestingatashorterviewingdistance(forlowvision);• Tosmallervaluesbytestingatalongerviewingdistance(fornormalvision).

Thevaluesofangularprintsizewillbeadjustedinaccordancewiththeselectedviewingdistance.Theviewingdistancecanbemodified:

• Fromthehomescreen,bychangingthevalueusingthe‘+’and‘-‘buttonsbeforerunningatest;

• Throughthesettingsbyenteringthedesiredvalueinthe‘Viewingdistance’field.ThevaluesetherewillbeusedasadefaultforsubsequenttestsandcanbeoverwrittenfromtheHomeScreen.

SeetheHelpfulTipsbelowforsuggestedvaluesofviewingdistance.Thesevaluesareofferedforguidanceonly.

8.2 ContrastpolarityBydefault,thecontrastpolarityissettothestandardblack-on-white.Toenablethereversedcontrastpolarityoption(white-on-black),clickonthebutton“SETTINGS”fromthehomescreenandenablethe‘Reversepolarity’option.

8.3 LanguageFivelanguagesarecurrentlysupportedbytheMNREADapp:English,Italian,French,SpanishandPortuguese.Toenableaspecificlanguage,clickonthebutton“SETTINGS”fromthehomescreen,openthe‘Language’fieldandselectthelanguagedesired.

• LowVision:20to40cm(8to16inches)• NormalVision:60to80cm(24to32inches)

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8.4 ExternalkeyboardToconnectanexternalkeyboardviaBluetooth,firstmakesurethattheBluetoothoptionisenabledonyourdevice.Openthe“Settings”appofyouriPadandgotounder“Bluetooth”.First,makesuretheBluetoothoptionisturnedon.Identifyyourkeyboardinthelistofdevices,andconnectittoyouriPad.ToturntheBluetoothkeyboardoptiononintheMNREADapp,goto“SETTINGS”andenablethe‘Keyboard’option.Notethattoclosethekeyboardafterenteringsomethinginthe“testid”or“notes”fieldsonthehomescreen,onehastopressthekeyboardicononthelowerrighthandsideofthekeyboard.

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Seethe“Tips”boxbelowforalistofkeyfunctions.

8.5 OperatoremailOnecansharetestresultsviaemail.Ifthesameemailaddressisusedfrequently,onecansetupadefaultrecipientaddressinthe“Operatoremail”field.

8.6 SizeunitPrintsizecanbeexpressedbothinangularandphysicalunits.Angularunitsaredependentontheviewingdistance,whereasphysicalunitsarenot.HerearealltheprintsizeunitsavailableintheMNREADapp:

• Angularprintsizes• LogMAR• BritishSnellennotation(20/200forexample)• MetricSnellennotation(6/60forexample)• Decimal(0.1forexample)

• Physicalprintsizes• SloanM• FontSizeinpoints

Throughoutthetest,printsizewillbeexpressedinbothangularandphysicalunits.Toselecttheunitstouse,clickonthebutton“SETTINGS”fromthehomescreen,openthe“Printsizeunit”fieldandselectthedesiredangularandphysicalunits.

HomeScreen Numeric1-5tochooseachart

Spacebarto“START”atest

Pre-stimulus Spacebarto"Go"

Stimulusscreen Spacebartoendpresentation

Scoringscreen0-9and10-19forscoringU=unabletoreadI=ignore

Resultscreen Nokey-mustusetouches

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9. LightingConditions&BrightnessMNREADtestingshouldbeconductedunderstandardizedlightingconditions.ThetestlightlevelrecommendedbytheNationalAcademyofSciencesandbytheAmericanNationalStandardsInstituteforETDRSisaminimumluminanceof85cd/m2.Werecommendsettingthebrightnessleveltoabout75%ofthemaximumbrightnesslevelprovidedbytheiPaddisplay.Todoso,goto“SETTINGS”andenter75inthefield‘Brightness(0-100)’.ThissettingwilloverwritethegeneralBrightnessoftheiPadONLYwhenusingtheMNREADapp.

• ThepercentagestoredtheappSettingsreferstothebrightnessratioofawhitescreentothemaximum(white)luminancethatthescreencanshow.

• TheiPadscreenatitsmaximumbrightnessis400cd/m2.• A75%settingproducesa300cd/m2backgroundinnormal-polaritytests.

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10. Appendix

10.1 ConversiontablebetweenlogMARandSnellenacuityunits

viewing distance logMAR viewing distance logMARcm inches correction* cm inches correction4 1.6 +1.00 44 17.3 –0.048 3.1 +0.70 48 18.9 –0.08

12 4.7 +0.52 52 20.5 –0.1116 6.3 +0.40 56 22.0 –0.1520 7.9 +0.30 60 23.6 –0.1824 9.4 +0.22 64 25.2 –0.2028 11.0 +0.15 68 26.8 –0.2332 12.6 +0.10 72 28.3 –0.2636 14.2 +0.05 76 29.9 –0.2840 15.7 +0.00 80 31.5 –0.30

logMAR Snellen* logMAR Snellen logMAR Snellen logMAR Snellen1.90 20/1589 6/477 1.30 20/399 6/120 0.70 20/100 6/30 0.10 20/25 6/81.88 20/1517 6/455 1.28 20/381 6/114 0.68 20/96 6/29 0.08 20/24 6/71.86 20/1449 6/435 1.26 20/364 6/109 0.66 20/91 6/27 0.06 20/23 6/71.84 20/1384 6/415 1.24 20/348 6/104 0.64 20/87 6/26 0.04 20/22 6/71.82 20/1321 6/396 1.22 20/332 6/100 0.62 20/83 6/25 0.02 20/21 6/61.80 20/1262 6/379 1.20 20/317 6/95 0.60 20/80 6/24 0.00 20/20 6/61.78 20/1205 6/362 1.18 20/303 6/91 0.58 20/76 6/23 -0.02 20/19 6/61.76 20/1151 6/345 1.16 20/289 6/87 0.56 20/73 6/22 -0.04 20/18 6/51.74 20/1099 6/330 1.14 20/276 6/83 0.54 20/69 6/21 -0.06 20/17 6/51.72 20/1050 6/315 1.12 20/264 6/79 0.52 20/66 6/20 -0.08 20/17 6/51.70 20/1002 6/301 1.10 20/252 6/76 0.50 20/63 6/19 -0.10 20/16 6/51.68 20/957 6/287 1.08 20/240 6/72 0.48 20/60 6/18 -0.12 20/15 6/51.66 20/914 6/274 1.06 20/230 6/69 0.46 20/58 6/17 -0.14 20/14 6/41.64 20/873 6/262 1.04 20/219 6/66 0.44 20/55 6/17 -0.16 20/14 6/41.62 20/834 6/250 1.02 20/209 6/63 0.42 20/53 6/16 -0.18 20/13 6/41.60 20/796 6/239 1.00 20/200 6/60 0.40 20/50 6/15 -0.20 20/13 6/41.58 20/760 6/228 0.98 20/191 6/57 0.38 20/48 6/14 -0.22 20/12 6/41.56 20/726 6/218 0.96 20/182 6/55 0.36 20/46 6/14 -0.24 20/12 6/31.54 20/693 6/208 0.94 20/174 6/52 0.34 20/44 6/13 -0.26 20/11 6/31.52 20/662 6/199 0.92 20/166 6/50 0.32 20/42 6/13 -0.28 20/10 6/31.50 20/632 6/190 0.90 20/159 6/48 0.30 20/40 6/12 -0.30 20/10 6/31.48 20/604 6/181 0.88 20/152 6/46 0.28 20/38 6/11 -0.32 20/10 6/31.46 20/577 6/173 0.86 20/145 6/43 0.26 20/36 6/11 -0.34 20/9 6/31.44 20/551 6/165 0.84 20/138 6/42 0.24 20/35 6/10 -0.36 20/9 6/31.42 20/526 6/158 0.82 20/132 6/40 0.22 20/33 6/10 -0.38 20/8 6/31.40 20/502 6/151 0.80 20/126 6/38 0.20 20/32 6/10 -0.40 20/8 6/21.38 20/480 6/144 0.78 20/121 6/36 0.18 20/30 6/9 -0.42 20/8 6/21.36 20/458 6/137 0.76 20/115 6/35 0.16 20/29 6/9 -0.44 20/7 6/21.34 20/438 6/131 0.74 20/110 6/33 0.14 20/28 6/8 -0.46 20/7 6/21.32 20/418 6/125 0.72 20/105 6/31 0.12 20/26 6/8 -0.48 20/7 6/2

time speed* time speed time speed time speed time speed1.0 600 3.4 176 5.8 103 8.2 73 13.5 441.1 545 3.5 171 5.9 102 8.3 72 14.0 431.2 500 3.6 167 6.0 100 8.4 71 14.5 411.3 462 3.7 162 6.1 98 8.5 71 15.0 401.4 429 3.8 158 6.2 97 8.6 70 15.5 391.5 400 3.9 154 6.3 95 8.7 69 16.0 381.6 375 4.0 150 6.4 94 8.8 68 16.5 361.7 353 4.1 146 6.5 92 8.9 67 17.0 351.8 333 4.2 143 6.6 91 9.0 67 17.5 341.9 316 4.3 140 6.7 90 9.1 66 18.0 332.0 300 4.4 136 6.8 88 9.2 65 18.5 322.1 286 4.5 133 6.9 87 9.3 65 19.0 322.2 273 4.6 130 7.0 86 9.4 64 19.5 312.3 261 4.7 128 7.1 85 9.5 63 20.0 302.4 250 4.8 125 7.2 83 9.6 63 21.0 292.5 240 4.9 122 7.3 82 9.7 62 22.0 272.6 231 5.0 120 7.4 81 9.8 61 23.0 262.7 222 5.1 118 7.5 80 9.9 61 24.0 252.8 214 5.2 115 7.6 79 10.5 57 25.0 242.9 207 5.3 113 7.7 78 11.0 55 26.0 233.0 200 5.4 111 7.8 77 11.5 52 27.0 223.1 194 5.5 109 7.9 76 12.0 50 28.0 213.2 188 5.6 107 8.0 75 12.5 48 29.0 213.3 182 5.7 105 8.1 74 13.0 46 30.0 20

© 1994 Regents of the University of Minnesota

* reading speed = 600 / (reading time in seconds)

*Snellen denominator = Snellen numerator × 10 and has been rounded to the nearest integer.

Table A LogMAR adjustments for non-standard viewing distances

Table C Conversion between reading time (seconds) and reading speed (wpm) for the MNREAD sentences

Table BConversion between logMAR and Snellen acuity

* correction = log [ 40 / (viewing distance in cms) ]10

(logMAR acuity)

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10.2 ConversiontablebetweenlogMAR,fontsizeandMunitsInordertoshareresultswithpatientsinacomprehensiblemanner,theappusesfontsize(inpoints)toexpressprintsizevalues.Thankstothisfeature,itwillbeeasytogivethepatientsanestimateoftheirCriticalPrintSizetohelpthemoptimallysetthefontsizeontheircomputerscreen.BelowisatablesummarizingtheconversionbetweenLogMAR,Fontsize(Pt)andM.

LogMAR(at40cm)

FontSize(Pt)

M

2.0 370 --1.9 295 --1.8 235 --1.7 185 --1.6 150 --1.5 120 --1.4 90 --1.3 75 --1.2 60 6.31.1 46 5.01.0 38 4.00.9 30 3.20.8 24 2.50.7 18 2.00.6 14 1.60.5 12 1.30.4 9.2 1.00.3 7.4 0.80.2 5.9 0.60.1 4.6 0.50.0 3.7 0.4-0.1 2.9 0.32-0.2 2.3 ---0.3 1.8 --