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Explore methods to improve vision testing accuracy for driving licenses, addressing legal, medical, and reliability aspects. Learn about quality deficits and potential solutions.
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How to circumvent quality deficits in eye testing and driving licensing!? KjellOhlsson Professor of Engineering Psychology/Human Machine Interaction Department of Management & Industrial Engineering, Division of Quality Technology & Management, Linköping University Scientific advisor to the Institute for Humane Technology (IHT), Bollnäs Also affiliated to the Swedish Centre for Stress Medicine E-mail: kjell.ohlsson@liu.se Mobile: +46 702421687
Car driving as a civil right • Before an authoritydeprives a citizen a commonlyconceived civil right or a privilege the burdenofevidence is casted on the authority and not on the individualcitizen. • The authority is alsoresponsible for providing solid evidence for its actions and firm motivation ofitsdecisions. • Decisionsshouldalso be possibletoappealagainst in a democraticstate.
Equalitybefore the law • All citizensexpectto be treatedequally by the government and itsauthorities. • A minor part ofpeoplewithvisualimpairmentsaretested. • Since 2008 wehave a common anti-discriminationregulation at the EU-level, implyingthatnobodyshould be discriminateddueto race, etnicity, religion, sexual preferences and functional disorders etcetera.
The situation oftoday for patients in Sweden • New legislationdemands on physicianstoreport all patients thatmayhavemedicalconditionsthataffecttheirdrivingcapabilityhaveincreasednumberof patients loosingtheirlicenses • A stronglyselectivetestingof patients • Arguments from laymenaretotallyignored in a legal process
The holisticview on patients is forgotten • Total life situation should be considered • Obsolete focus on field-of-viewtesting • Hippocrates’ oathaimstoprotectionof the patient • Common sense is absolutelynecessary, but not sufficient for withdrawalof a drivinglicense • The attribution of causal relationships amongmanyphysiciansoftodaybelongsto a medevial whitch process
Vision and drivingbehaviour • No scientificunequivocalevidence for a positive relationship betweensizeoffield-of-view and drivingperformance. Lowvision does not neccessarily makes you a bad driver! • Legislationis basedon falsepremises • Statistical data supportingdesicionmakersarealmostnonexistent • ”practitionerstraditional best practice and medicalevidence” reflectssuperstitiousbehaviour
Visual perception • Visual perception is entirelydependent on movementdynamics • Perception is selective • Sometimes it is a hugedifferencebetweenwhatyouarelooking at and whatyouactuallypercieve (inattentionalblindness) • Car driving is to 90-95% connectedtoafferentvisual input? • Seeing is believing (person related)
Definitions: • Central (focal) vision: - an area limited by a radiusof 2 angledegrees from the focalpoint (The Swedish Transportation Board: - An area limited by a radiusof 30 angledegrees from the focalpoint) Note the logarithmicdecrease in acuity from the focalpoint. • Peripheral vision: The entire area of the field-of-viewoutside the tiny area defined as central vision.
Definitions:Contin. • Functionalfield-of-view : 7 angledegrees from the focalpoint • Functionalfieldofgaze: The area aheadthat is practicallyviewedif the driver has the possibilitytomoveeyes and headin a drivingcontext.
The conceptofvisualcapability • Field-of-view tests areessential for: • Tracingofdiseases, • Correctdiagnoses • Providing ample treatment • Appropriateevaluationoftreatmentoutcome • But not particularlyuseful for assesmentofpeoples’ drivingskills!
Fundamental quality problems withfield-of-viewtesting • Lack ofvalidity(-what is intendedto be measured? Driving skills? - or prerequisites for keeping a drivinglicense? • Conceptualvalidity(based on theoretical underpinnings) • Ecologicalvalidity(based on familiar tasks) • Concurrentvalidity(connectiontoother tests ofdrivingperformance)
Fundamental quality problems withfield-of-viewtestingContin. • Predictivevalidity(the degreetowhich a certain test method is empiricallyanchored and towhatextent the test resultsmaypredictfuturebehaviourof the testees) • Face validity(measurementofwhat is intendedto be measured in connectionwith a welldefinedpurpose)
Otherpertinentqualitydeficiencies in connectiontofield-of-viewtesting • Lack ofreliability • Randomeffects • Who is subjectedtoadvancedfield-of-view tests? • Which tests areused? • Whichcriteriaareused for passing or failing a specific test? • Shortcomings in reference data? The status ofvisualcapability in the entire population ofcar drivers?
Otherpertinentqualitydeficiencies in connectiontofield-of-viewtestingContin. • Internalreliability • Test –retestreliability • Same test at different occations • Different tests aming at measurementof the same variables
The conceptofdrivingcapabilityalso lacks validity • Toomany definitions are in use • Many different dependentvariablesareused, withvaryingcriteria • Manyattempts has beenmadetouse experimental designs withinduced independent variables • No unifiedoperationalizationof the conceptofdrivingcapability
Validity problems ofcar simulators • A car simulator could never yieldtop scores on validity • Validity problems withcar simulators wasan issuemorethan 20 yearsago, but not anylonger. Even the simpliestlowfidelity simulator is far betterwithrespecttovaliditythan the best field-ofview test for assessingdrivingcapability • VIP-project at VTI aimsto a harmonizationofcar simulators in Sweden
Problems with the conceptofdrivingcapability • Sloppy and heterogenous definitions • Pooroperalisationof general requirements • Manydependentvariablesused in order toassessdrivingcapability • No singlecriterion for acceptable drivingbehaviour • Usuallyonlysubjectivejudgementsareused for withdrawalofdrivinglicenses
Problems with the conceptofdrivingcapabilityContin. • Physiciansassesspeoplesdrivingcapabilitywithoutany formal educationofdrivingassessment • Physiciansassessingpeoplesdrivingcapabilitythroughfield-of-view tests haverarelytheirspecialities in ophtalmology, visual perception or psycho-physiology. • Physiciansassessingpeoplesdrivingcapability at the Swedish Transportation Board never meet the patients
Problems with the conceptofdrivingcapabilityContin. • Reliable and valid data on peoples’ drivingskillsareeasilycollected in car simulators, buttheseare not allowed and certified by The Swedish Transportation Board (despite Sweden hostsoneof the mostadvancedcar simulator parks in the world) • No acceptable driver centredquantifiable risk assessment is done by authorities or physicists • Weactuallydon’tknow the drivingprofileof the averagecar driver during normal driving(Accident analyses indicatesaferdrivingamong the patient population withfield-of-viewdeficiencies)
Problems with the conceptofdrivingcapabilityContin. • Whatwe do know is that the averagecar driver behaveworsethanexpected • Ordinarycar drivers withoutanyvisual problems mightfail a simulator test? Fine, maybethesecar drivers needtorefreshtheirskills. • What is the mostsuitablereferencegroup for peoplewitheye problems dueto a stroke/strokes?