Evaluation of computer-based testing for aniseikonia in children.

Purpose: To evaluate the ability of children to perform computer-based matching and to evaluate the accuracy and reliability of size lens induced aniseikonia measurement using the Aniseikonia Inspector version 1.
Methods: Fifty-seven children in grades 1, 3, and 5 (aged 6 to 11 years) completed four trials per each of four conditions: control (associated binocular), dissociated (wearing red/green filters only), and dissociated with 3.5% afocal (size) lens over the right eye and size lens over the left eye (the latter two conditions in predetermined random order). Children adjusted the size of a variable semicircle seen by one eye in 0.5% steps using computer arrow keys to match the size of a nonvariable semicircle seen by the other eye. Testing was performed in the dark using large targets oriented vertically.
Results: The repeatability coefficient (sw), based on individual measures, was lowest for the control condition. Repeated measures (mean of four trials) show that adjustments with red/green dissociation only were not significantly different from zero size difference, with narrow confidence limit widths at all ages (0.54, 0.42, and 0.22% at grades 1, 3, and 5, respectively). Repeated measures of induced aniseikonia showed increased confidence limit widths (width for right eye condition was 2.77, 0.71, and 0.82% at grades 1, 3, and 5, respectively). Measured aniseikonia (mean of four adjustments) was less than induced aniseikonia with slopes of regressions lines insignificantly <1.0 for all grades.
Conclusions: Children as young as 6 years are capable of making the adjustments necessary to obtain a measure of aniseikonia under dissociated conditions with sufficient accuracy and reliability to be clinically useful using the Aniseikonia Inspector software (version 1 with large targets in the dark). Further study is necessary to show how children with natural aniseikonia respond to testing.