Effects of task explanation on stereoacuity measurements using a random-dot stereotest

Accurate stereoacuity assessment is essential for evaluating binocular vision, yet non-visual factors such as instruction quality and task execution time might influence performance on random-dot stereotest in adults with normal binocular vision.

In this randomized controlled study, 100 adults (mean age 26.4 ± 5.17 years) with normal binocular vision were assigned to a control group (n = 40) or an experimental group (n = 60). All participants completed two consecutive administrations of the Random Dot 2 Stereo Acuity Test with LEA Symbols in an immediate test-retest paradigm. In the control group, both administrations followed standard manufacturer instructions. In the experimental group, the second (retest) administration was preceded by a detailed explanation supported by visual examples of possible target shapes. Stereoacuity (in arcseconds) and test completion time (in seconds) were recorded to evaluate the effect of enhanced instruction on retest performance.

The control group showed no significant change in stereoacuity between measurements (mean change: 0.03 log10 arcsec, p = 0.125). In contrast, the experimental group demonstrated a significant improvement (mean change: 0.45 log10 arcsec, p < 0.0001), with most participants reaching the test's finest disparity level (63 arcsec). Changes in response time did not differ between groups (p = 0.063). However, in the experimental group, greater improvements in stereoacuity were strongly associated with longer post-test response times (p < 0.0001).

Enhanced instructions with visual cues significantly improved stereoacuity outcomes beyond expected test-retest variability, highlighting the importance of instruction quality and task engagement in stereopsis assessment, which should be carefully considered in both clinical practice and research settings.