title: Measuring Infant Visual Acuity with Gaze Tracker Monitored Visual Fixation.
abstract: OBJECTIVE
  To validate a method of measuring grating acuity with remote gaze tracking (GT) against a current clinical test of visual acuity (VA), the Teller Acuity Cards (TACs), as part of the development of an automated VA test for infants.
  
  
  METHODS
  Visual acuity for computer-generated horizontal square-wave gratings was determined from relative fixation time on a grating area compared with the background. In experiment 1, binocular VA was based on eye movements with a GT in 15 uncorrected myopic adults and compared with VA measured with subjective responses with the same stimuli and with the TACs. In experiment 2, binocular VA was determined in 19 typically developing infants aged 3 to 11 months on two visits with both the GT and TACs.
  
  
  RESULTS
  In adults, the mean difference between VA measured by the GT and TACs was 0.01 log cycles per degree (cpd) and the 95% limits of agreement were 0.11. One hundred percent of GT VA results were within 0.5 octave of the TACs' VAs. The mean difference between the GT and TACs for infants was 0.17 log cpd on both the first and second visit (95% limits of agreement, 0.42 and 0.47, respectively). The mean difference between test and retest for infant GT VA was 0.06 log cpd, and limits of agreement for repeatability were 0.48 log cpd. In infants, both the TACs and the GT had a reliability of 89% within less than or equal to 1 octave between visits. Gaze tracking VA improved with age and is in agreement with published norms.
  
  
  CONCLUSIONS
  The agreement between the TACs and GT in adults and infants validates the method of measuring grating acuity with the remote GT. These results demonstrate its potential for an automated test of infant VA.
authors.affiliation: *BOptom, MSc †PhD, FCOptom, FAAO ‡OD, PhD §BOptom, PhD ∥PhD School of Optometry and Vision Science, University of Waterloo, Ontario, Canada (ARH, SJL, ELI, KN); and Institute of Biomaterials and Biomedical Engineering, University of Toronto, Ontario, Canada (ME).
authors.forename: Amithavikram R
authors.initials: AR
authors.lastname: Hathibelagal
authors.forename: Susan J
authors.initials: SJ
authors.lastname: Leat
authors.forename: Elizabeth L
authors.initials: EL
authors.lastname: Irving
authors.forename: Krithika
authors.initials: K
authors.lastname: Nandakumar
authors.forename: Moshe
authors.initials: M
authors.lastname: Eizenman
mesh_terms: D000328:Adult; D005133:Eye Movements / Q000502:physiology; D005260:Female; D005403:Fixation, Ocular / Q000502:physiology*; D005865:Gestational Age; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic; D015203:Reproducibility of Results; D014787:Vision Tests / Q000379:methods; D015348:Vision, Binocular / Q000502:physiology; D014792:Visual Acuity / Q000502:physiology*; D055815:Young Adult