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Updated: Apr 12, 2026
Author Spotlight: An Automated Method for Assessing Visual Acuity in Infants and Toddlers Using an Eye-Tracking System
Published on: March 17, 2023
Measuring Infant Visual Acuity with Gaze Tracker Monitored Visual Fixation
Amithavikram R Hathibelagal1, Susan J Leat, Elizabeth L Irving
1*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).
Insights
Remote gaze tracking (GT) effectively measures grating acuity, showing strong agreement with Teller Acuity Cards (TACs) in adults and infants. This validates GT as a potential automated method for infant visual acuity (VA) testing.
Area of Science:
- Ophthalmology
- Pediatric Medicine
- Biomedical Engineering
Background:
- Assessing visual acuity (VA) in infants is crucial for early detection of visual impairments.
- Current methods like Teller Acuity Cards (TACs) can be challenging to administer to infants.
- Development of automated, objective VA testing methods is needed.
Purpose of the Study:
- To validate a remote gaze tracking (GT) method for measuring grating acuity.
- To compare GT measurements against the established clinical standard, Teller Acuity Cards (TACs).
- To assess the potential of GT for automated infant VA testing.
Main Methods:
- Grating acuity was measured using computer-generated square-wave gratings and relative fixation time.
- Experiment 1: Binocular VA measured with GT in 15 uncorrected myopic adults, compared to subjective responses and TACs.
- Experiment 2: Binocular VA measured with GT and TACs in 19 infants (3-11 months) over two visits.
Main Results:
- In adults, GT and TACs showed excellent agreement (mean difference 0.01 log cpd, 95% limits 0.11).
- In infants, GT and TACs demonstrated good agreement (mean difference 0.17 log cpd, 95% limits 0.42-0.47).
- Infant GT showed good repeatability (mean difference 0.06 log cpd) and reliability (89% within 1 octave).
Conclusions:
- Remote gaze tracking is a valid method for measuring grating acuity in both adults and infants.
- The validated GT method shows significant potential for developing an automated infant VA test.
- This technology could improve early diagnosis and management of visual disorders in infants.
Purpose:
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.
