A frequency-tagging electrophysiological method to identify central and peripheral visual field deficits

Area of Science:

• Ophthalmology
• Neuroscience
• Clinical Electrophysiology

Background:

• Assessing visual field integrity is crucial, especially in pediatric populations.
• Existing methods can be time-consuming and challenging for young children.
• A need exists for a rapid and efficient electrophysiological protocol for visual field testing.

Purpose of the Study:

• To develop and validate a fast and efficient electrophysiological protocol for examining visual field integrity.
• To assess the protocol's utility in pediatric testing.
• To evaluate the impact of age and gaze deviation on the electrophysiological signals.

Main Methods:

• Utilized steady-state visual-evoked potentials (ssVEPs) with field-specific radial checkerboards at 7.5 Hz (central) and 6 Hz (peripheral).
• Recorded responses from 22 healthy participants (5-34 years) and 5 visually impaired adolescents.
• Investigated responses at multiple electrode sites (Oz, POz, O1, O2) and the effect of gaze deviation.

Main Results:

• ssVEP responses were consistent across electrode sites, with a stronger central signal at Oz.
• The protocol demonstrated high sensitivity in detecting gaze deviation.
• No significant effects of age or sex were observed in healthy participants; visual acuity correlated with the central signal.

Conclusions:

• A single electrode at Oz is sufficient for capturing central and peripheral visual signals and monitoring gaze deviation.
• The developed ssVEP protocol is fast, reliable, efficient, and suitable for children as young as 5.
• Further studies with larger pediatric cohorts are recommended to establish clinical norms.