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

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.