Clinical Research Directory

Inclusion Criteria: * Adult: ≥ 18 years and ≤ 60 years * Individual who has given oral consent * Individual who has been fasting (no food, drink, or tobacco) for at least 1 hour prior to PEG and PEO measurement * No cognitive complaints and normal neurological examination. * Group of patients with visual impairment: A. Central: documented bilateral macular dystrophy (e.g., Stargardt disease, Best disease) with confirmed central scotoma (CV 24.2, 10.2, or 30.2). B. Peripheral: documented bilateral peripheral retinal dystrophy with confirmed peripheral involvement (CV 30-2 or 24-2). • Control group: a person with normal vision and no known ophthalmological abnormalities (normal visual acuity and fundus examination) who is precisely matched by sex and smoking status (former smoker who has quit vs. nonsmoker), and approximately matched by age (± 5 years) to a visually impaired participant included in the study. Exclusion Criteria: For this group: patients with visual impairments: * Individuals who are not enrolled in or eligible for a social security program * Individuals subject to a legal protective measure (guardianship, conservatorship) * Individuals subject to judicial safeguard measures * Adults who are legally incapacitated or unable to give informed consent * Documented COVID-19 infection within the 6 months prior to enrollment * Active smokers (≥1 cigarette per day) or users of any other inhaled substances (water pipe, cannabis, etc.) * Participants following a sugar-free diet * Participants with diabetes, of any type * Participants taking medication (ongoing during the study) that interferes with taste perception • Pregnant or breastfeeding women * Individuals with neurodegenerative diseases (Parkinson's, Alzheimer's) * Individuals with braids, dreadlocks, or any other hairstyle that prevents electrodes from being placed in sufficiently precise locations on the scalp. * Overweight subjects with a BMI ≥ 35 kg/m²