title: The Handy Eye Check: a mobile medical application to test visual acuity in children.
abstract: OBJECTIVE
  To compare visual acuity results obtained with the Handy Eye Chart to results obtained using the Handy Eye Check, a mobile medical application that electronically presents isolated Handy Eye Chart optotypes according the Amblyopia Treatment Study (ATS) protocol.
  
  
  METHODS
  Consecutive patients 6-18 years of age presenting for eye examinations between May 30, 2012, and June 26, 2012, were invited to participate. Monocular visual acuity testing was performed on the subject's poorer-seeing eye using both the Handy Eye Check and the Handy Eye Chart under the same conditions. Visual acuity was first tested using the mobile application, then using the chart, followed by repeated application testing. Patients were excluded if they were unable to undergo the required visual acuity testing or if visual acuity in the worse-seeing eye was less than 20/200 (for validity testing, but not reliability testing).
  
  
  RESULTS
  There was a strong linear correlation (r = 0.92) and a mean difference in acuity of -0.005 logMAR, or less than one letter (95% CI, -0.03 to 0.02), between the two tests. The 95% limits of agreement were ± 2 lines. Test-retest reliability was high, with 81% of retest scores within 0.1 logMAR (5 letters) and 100% within 0.2 logMAR (10 letters), an intraclass correlation coefficient of 0.93, and a standard error of measurement of 0.08.
  
  
  CONCLUSIONS
  The Handy Eye Check mobile application compares similarly to the Handy Eye Chart as a valid and reliable test of visual acuity in children age 6-18 years.
authors.affiliation: Department of Ophthalmology, Emory University School of Medicine, Atlanta, Georgia.
authors.forename: Keri N
authors.initials: KN
authors.lastname: Toner
authors.affiliation: Department of Ophthalmology, Emory University School of Medicine, Atlanta, Georgia; Department of Biostatistics and Bioinformatics, Rollins School of Public Health of Emory University, Indianapolis, Indiana.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Lynn
authors.affiliation: Indiana University School of Optometry, Indianapolis, Indiana.
authors.forename: T Rowan
authors.initials: TR
authors.lastname: Candy
authors.affiliation: Department of Ophthalmology, Emory University School of Medicine, Atlanta, Georgia. Electronic address: amy.hutchinson@emory.edu.
authors.forename: Amy K
authors.initials: AK
authors.lastname: Hutchinson
mesh_terms: D000293:Adolescent; D002648:Child; D034201:Computers, Handheld; D005260:Female; D006801:Humans; D008297:Male; D063731:Mobile Applications; D015203:Reproducibility of Results; D014787:Vision Tests / Q000295:instrumentation*; D014792:Visual Acuity / Q000502:physiology*