Flickering light and geometric hallucinations (Amaya 2023)

Rhythmic light flicker reliably induced geometric hallucinations and phosphenes in sober participants, peaking around 10 Hz. An arrhythmic control with matched luminance strongly reduced the effect.

A plain-language summary from binaural's reading notes, edited by Jude Mc. Last updated 10 November 2026. Not medical advice.

The question: Does rhythmic flickering light induce hallucination-like visual patterns, and does the flicker frequency matter?

What it found

• Rhythmic flicker induced geometric (Klüver-form) hallucinations and phosphenes in sober participants, peaking around 10 Hz.
• An arrhythmic control with matched luminance strongly reduced the effect, which points to a neural entrainment mechanism rather than a retinal afterimage.
• A 2025 fMRI follow-up gives a thalamocortical correlate of the effect.
• Evidence specific to the commercial stroboscopic device Lucia N°03, which uses this effect, is thin: small samples (n of about 20–24), largely one research cluster, and an often-cited EEG study that remains a preprint.

Limits

• There are no sham-controlled clinical trials of stroboscopic-light devices.
• Responses vary heavily between individuals (the trait of absorption).

Where this sits

More in the library on light, flicker and 40 hz. For the wider picture, read 40 Hz, gamma and the brain.

This is our plain-language reading of the paper. It is not medical advice, and one study rarely settles a question.