# Optimizing cyclopean stimuli for the evaluation of stereo vision by steady-state visual evoked potentials

## TL;DR

This study optimized visual stimuli to measure stereo vision using brainwave responses, finding that a specific stimulus frequency worked best with minimal electrodes.

## Contribution

The study introduces optimized cyclopean stimuli for reliable and efficient ssVEP-based assessment of stereopsis.

## Key findings

- DRDC at 1.875 cps evoked significant ssVEP responses in 93% of participants using occipital electrodes.
- Monocular control measurements confirmed stereo-specificity of the responses.
- Optimized DRDC stimuli support clinical assessments for non-verbal or pediatric populations.

## Abstract

This study aimed to optimize dynamic random dot correlogram (DRDC) and stereogram (DRDS) stimuli to evoke steady-state visual evoked potentials (ssVEP) on multiple EEG channels for the objective assessment of stereopsis.

EEG recordings were conducted on 22 healthy adults (mean age: 30.2 ± 5.8 years) while viewing cyclopean and control stimuli. DRDC and DRDS were presented at three temporal frequencies (0.9375, 1.875, and 3.75 cycles per second, cps) using anaglyphic channel separation. The ssVEP responses were analyzed using T2circ statistical test to determine the most effective stimulus for eliciting significant cortical activity.

DRDC at 1.875 cps evoked significant ssVEP responses in 93% of participants on at least one occipital electrode (O1, Oz, O2) and in 100% when including parietal-occipital electrodes. DRDS at similar frequencies also produced robust responses but required additional parietal electrode monitoring. Monocular control measurements confirmed that responses were stereo-specific.

DRDC at 1.875 cps was the most effective stimulus for objective electrophysiological assessment of stereopsis, demonstrating high reliability with minimal electrode setups. These findings support the integration of optimized ssVEP protocols into clinical assessments, particularly for non-verbal or pediatric populations.

The online version contains supplementary material available at 10.1007/s10633-025-10059-6.