RecruitingNot Applicable

Study of Visual Perception Phenomena: Phosphene Mapping Induced by TMS and Its Relationship With Eye Movements

Russia50 participantsStarted 2025-09-10

Plain-language summary

The purpose of this basic science study is to better understand human visual perception. Phosphenes are flashes of light that can be induced using Transcranial Magnetic Stimulation (TMS). The location of these phosphenes is known to change with eye movements, but the exact influence of these movements is not fully understood. The main questions this study aims to answer are: How does stimulating specific areas of the visual cortex relate to where a person perceives a phosphene? How do eye movements affect the accuracy of mapping these sensations? The study will enroll three groups of adults (aged 18-65): patients with Visual Snow Syndrome, color-blind participants, and healthy volunteers. During the experiment, participants will receive single-pulse TMS to their visual cortex. Simultaneously, their eye movements will be monitored with an eye-tracker, and their brain activity will be recorded with EEG. Participants will be asked to report the location of the perceived light flashes. This will help create a map of the brain areas responsible for visual sensations and clarify how eye movements influence this process.

Who can participate

Age range

18 Years – 65 Years

Sex

ALL

See this in plain English?

AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.

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 (…

Questions worth asking your doctor

Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.

1Based on my diagnosis and history, is this trial worth exploring for me — or is there a standard treatment we should try first?
2What does this trial's phase tell us about how much is already known about its safety and benefit?
3What would taking part actually involve for me — visits, tests, time, and travel?
4What are the known and possible risks or side effects I should weigh, and how would they be monitored?
5If this trial isn't the right fit, what other options or trials would you suggest I look into?

Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.

Questions for the trial coordinator

The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.

1What does taking part actually involve week to week — how many visits, where, and how long does each one take?
2What costs are covered by the study, and what might I have to pay for myself, including travel, parking, or time off work?
3What happens during screening, and what happens if the study team confirms I don't meet the criteria after those tests?
4Who pays for the scans, blood work, and other tests the trial requires — the study, my insurance, or me?
5How will being in the trial affect my regular care, and will my own doctor stay informed and involved?
6Can I leave the trial at any point if I change my mind, and what would happen to my care if I do?

A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.

What they're measuring

Topographic Map of Phosphene Localization

Timeframe: During the single study visit (session duration is 4 hours).

Trial details

NCT IDNCT07110493

SponsorSkolkovo Institute of Science and Technology

Sponsor typeOTHER

Study typeINTERVENTIONAL

Primary completion2026-12-10

Contact for this trial

Akinshin R.

79999810206 Roman.Akinshin@skoltech.ru

View on ClinicalTrials.gov More Visual Snow Syndrome trials