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1、Connecting Visual Acuity with Daily Viewing Experience in Individuals with Low Vision,Walter Wu,PhDOSU College of Optometry,Visual Acuity,Visual Acuity(VA)is a widely used way measuring a persons ability to see small details(often assessed by letter acuity charts).Visual Acuity is often expressed in
2、 Snellen unit in the US:20/20 or better:Normal Vision20/40 or worse:Low Vision20/200 or worse:Legal BlindnessHowever,the acuity numbers does not tell us what a person can do or cant do in their daily life.,Visual Acuity Survey,100 Yes/No Questions.Each question(item)includes a familiar object viewed
3、 at a given viewing distance.,Results,385 Participants with VA ranging from-0.3 logMAR(20/10)to 2 logMAR(20/2000).Age between 18 and 93(40%older than 65;average:55.7).Participant A gave 80/100 yeses vs Participant B gave 80/100 yeses.,Vision Ability,Hard vs.easy:Longer distances/smaller targets are
4、harder questions;shorter/bigger are easier.How we score it:We use a standard method called Item Response Theory(IRT).Think of it as a smart ruler that learns how hard each question is and estimates each persons vision ability from their pattern of Yes/No answers.What the score means:A higher ability
5、 score=more likely to see smaller/farther things;a lower score=needs things bigger/closer.,Vision Ability vs Visual Acuity,Estimated Vision Ability vs Measured visual Acuity,Estimate Visual Acuity,Estimate Visual Acuity from Vision Ability,Quick Summary,The results suggested that our participants vi
6、sion abilities,derived from their daily viewing experience,are highly correlated with their measured visual acuity values.The relationship between their vision abilities and visual acuity could be used to predict a new participants visual acuity based on their responses to the 100-item Visual Acuity