Eye movements may reveal Parkinson's progression

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

\*Inclusion Criteria: 1. Male or Female; 2. Clinically defined idiopathic Parkinson's Disease (PD); 3. Brain MRI performed in routine care in the 12 months preceding inclusion; 4. Cerebral DaTSCAN or cerebral PET with F-DOPA, performed as routine care before inclusion (no time limit), confirming presynaptic dopaminergic denervation; 5. Hoehn \& Yahr score: 1 to 3; 6. Normal clinical examination of oculomotricity (slight impairment of smooth pursuit accepted); 7. Neuro-cognitive disorders: absent or minor (according to DSM5); 8. Sufficient written and oral expression in French; 9. Covered by a health insurance system; 10. Written informed consent signed by the patient; 11. Presence of a caregiver. \* Exclusion Criteria: 12. Psychiatric comorbidity (except anxiety or mild to moderate depression); 13. Neurological comorbidity, if significant; 14. Brain MRI showing: 1. significant cerebrovascular pathology (Fazekas I admitted), 2. another brain disease, including stroke. 15. Major cognitive impairment; 16. Absolute exclusion criteria and "Red flags" of the 2015 criteria orienting towards another degenerative pathology of the extrapyramidal system: * Cerebellar syndrome * Vertical oculomotricity disorders on clinical examination * Motor symptoms restricted to the lower limbs * Bilateral and perfectly symmetrical parkinsonism * Early dystonia * Clinical profile suggestive of behavioral variant frontotemporal dementia (bvFTD) * Progressive aphasia or apraxia * Moderate or severe postural instability and / or early falls * Early bulbar dysfunction (dysarthria, swallowing disorders) * Ventilatory dysfunction (inspiration) * Severe dysautonomia * DOPA-resistance * Neuroleptic treatment or related 17. Normal MIBG myocardial scintigraphy (if performed).