Mapping TMS‑induced light flashes (phosphenes) while tracking eye movements

Is this trial a fit for you?

A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.

What this trial studies

Participants aged 18–65 will receive single‑pulse transcranial magnetic stimulation (TMS) to visual cortex while wearing an eye‑tracker and EEG cap and reporting where brief phosphenes appear. The study enrolls three groups: people with visual snow syndrome, people with diagnosed color vision disorders, and healthy controls. Researchers will map relationships among stimulation site, eye position, and reported phosphene location to see how gaze shifts affect perceived location. Results aim to clarify basic mechanisms of visual perception and improve methods for mapping cortical visual responses.

Why it matters

Who can join: the full rules

Inclusion Criteria:

For the "Patients with Visual Snow Syndrome" Arm:

Confirmed diagnosis of Visual Snow Syndrome according to the International Classification of Headache Disorders, 3rd edition (ICHD-3) criteria.

Presence of persistent, dynamic, tiny dots ("visual snow") across the entire visual field.

Presence of at least one of the following additional visual symptoms:

Palinopsia (prolonged afterimages). Photophobia (hypersensitivity to light). Nyctalopia (impaired night vision). Blurred vision. Patients whose symptoms appeared after a SARS-CoV-2 viral illness may be included.

For the "Color-blind Participants" Arm:

Presence of a color perception disorder. Must have a formal diagnosis of color blindness confirmed by specific ophthalmologic tests (e.g., Ishihara, Rabkin, Justova, or Stilling polychromatic plates, or the Farnsworth-Munsell test).

For the "Healthy Controls" Arm:

Absence of any active or past neurological, psychiatric, or ophthalmological disorders.

Exclusion Criteria:

General Criteria (Applicable to all participants):

Use of psychotropic drugs. Any contraindications to Transcranial Magnetic Stimulation (TMS), such as a history of epilepsy, seizures, or metallic implants in the head.

Pregnancy.

Specific to the "Patients with Visual Snow Syndrome" Arm:

Presence of any organic abnormalities in the eyes or visual system identified during a standard ophthalmologic examination.

Presence of comorbid psychiatric disorders or other medical conditions (e.g., migraine with aura) that could explain the symptoms.

Specific to the "Color-blind Participants" Arm:

Any non-congenital cases of color blindness. Presence of concomitant visual impairments that could affect visual perception independently of color blindness, such as cataracts, glaucoma, or macular degeneration.

Presence of concomitant neurological or psychiatric diseases, such as schizophrenia, epilepsy, or mood disorders, that could affect the study results.

Where it's running

• Skolkovo Institute of Science and Technology (Skoltech)
  Moscow, Russia Recruiting

Study contacts

• Study coordinator: Akinshin R.
• Email: Roman.Akinshin@skoltech.ru
• Phone: 79999810206

Similar studies

Other studies for the same condition or treatment. Recruiting studies are listed first.

• Brain function and visual adaptation in people with and without Visual Snow

  This project will test whether brain activity and responses to visual stimuli differ between adults with Visual Snow Syndrome, adults with migraine, and healthy adults.

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• 7T MRI scans for migraine, visual snow, and epilepsy

  This project will use high-field 7T MRI to try to find microstructural and network differences in people with migraine, visual snow, or drug‑resistant epilepsy and in healthy volunteers.

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• Evaluating a neuroprosthesis to reduce phantom limb pain and improve quality of life

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• Neuromodulation for relieving phantom limb pain

  This study is testing different ways to use electrical stimulation to help people who have had a limb amputated and are suffering from phantom limb pain feel better.

  Recruiting at 2 sites Skolkovo Institute of Science and Technology · Moscow, Moscow and 1 other locations · NCT06644807

How to take part

1. Review the eligibility criteria above with your treating physician.
2. Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
3. Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.