" The Eyes Have it " : Ocular Saccade Abnormalities in Prodromal Alzheimer's Disease

Inclusion Criteria: All patient groups: * Age \>60 years * Normal vision work-up : (corrected binocular visual acuity \> 8/10) * Written informed consent * Subjects affiliated to Social Security Group A: Prodromal AD. * Memory complaints. * Normal or slight restriction of IADL. * "hippocampal-type" amnesic syndrome defined by poor free recall despite adequate (and controlled) encoding, decreased total recall because of insufficient effect of cuing or impaired recognition, numerous intrusions (RL/RI-16items) * CDR (Clinical Dementia Rating Scale) ≥ 0,5 * Persistence of memory changes at a subsequent assessment (\>3 months) * Absence of global cognitive deterioration (MMSE ≥24) * Exclusion of other disorders that may cause mild cognitive impairment with adequate tests * 1.5 Tesla diagnosis MRI with at least T2, Flair transversal sections and coronal T1 sections in the coronal plan. Absent or slight medio temporal/hippocampal atrophy or if available (non mandatory) characteristic CSF betaA42/tau ratio Group B: Typical AD (mild to moderate) * NINDS-ADRDA diagnosis criteria * MMSE ≥ 20 Group C: Control subjects * No memory or other significant cognitive complain. * MMSE ≥ 24 Exclusion Criteria: All groups : * Clinically significant vision abnormality(P8 without glasses) * Oculomotor deficit or strabismus * Depression (GDS) with treatment * Subjects unable to give their informed consent Controls : * Memory or any other significant cognitive complain. * Abnormalities at inclusion (V0) neuropsychology testing suggestive of a cognitive deficit.