title: Computerized method of visual acuity testing: adaptation of the amblyopia treatment study visual acuity testing protocol.
abstract: OBJECTIVE
  To report a computerized method for determining visual acuity in children using the Amblyopia Treatment Study visual acuity testing protocol.
  
  
  METHODS
  A computerized visual acuity tester was developed that uses a programmed handheld device that uses the Palm operating system (Palm, Inc, Santa Clara, California). The handheld device communicates with a personal computer running a Linux operating system and 17-inch monitor. At a test distance of 3 m, single letters can be displayed from 20/800 to 20/12. A C program on the handheld device runs the Amblyopia Treatment Study visual acuity testing protocol. Using this method, visual acuity was tested in both the right and left eyes, and then the testing was repeated in 156 children age 3 to 7 years at four clinical sites.
  
  
  RESULTS
  Test-retest reliability was high (r =.92 and 0.95 for and right and left eyes, respectively), with 88% of right eye retests and 94% of left eye retests within 0.1 logarithm of minimal angle of resolution (logMAR) units of the initial test. The 95% confidence interval for an acuity score was calculated to be the score +/- 0.13 logMAR units. For a change between two acuity scores, the 95% confidence interval was the difference +/- 0.19 logMAR units.
  
  
  CONCLUSIONS
  We have developed a computerized method for measurement of visual acuity. Automation of the Amblyopia Treatment Study visual acuity testing protocol is an effective method of testing visual acuity in children 3 to 7 years of age.
authors.affiliation: Jaeb Center for Health Research, 3010 East 138th Ave., Suite 9, Tampa, Florida 33613, USA.
authors.forename: P S
authors.initials: PS
authors.lastname: Moke
authors.forename: A H
authors.initials: AH
authors.lastname: Turpin
authors.forename: R W
authors.initials: RW
authors.lastname: Beck
authors.forename: J M
authors.initials: JM
authors.lastname: Holmes
authors.forename: M X
authors.initials: MX
authors.lastname: Repka
authors.forename: E E
authors.initials: EE
authors.lastname: Birch
authors.forename: R W
authors.initials: RW
authors.lastname: Hertle
authors.forename: R T
authors.initials: RT
authors.lastname: Kraker
authors.forename: J M
authors.initials: JM
authors.lastname: Miller
authors.forename: C A
authors.initials: CA
authors.lastname: Johnson
mesh_terms: D000550:Amblyopia / Q000175:diagnosis / Q000628:therapy; D002648:Child; D002675:Child, Preschool; D002985:Clinical Protocols; D003201:Computers; D005260:Female; D006801:Humans; D008297:Male; D015203:Reproducibility of Results; D014787:Vision Tests / Q000295:instrumentation / Q000379:methods*; D014792:Visual Acuity