Case group selection criteria :  Inclusion Criteria:  Patient with clinically defined or probable primary ALS according to Airlie House criteria(1) Familial or sporadic form ≥18 years of age and ≤75 years of age Patient affiliated with a social security plan Informed consent signed by the patient  Exclusion Criteria:  Motor neuron disease mimicking ALS Pregnant or breastfeeding woman Treatment that may have a neuroprotective effect Any eye drops or treatments that may interfere with tear production Lens wearer Eye surgery ≤3 months Any ocular pathology other than ametropia, oculomotor disorder, amblyopia Any general pathology other than ALS with ocular repercussions Protective measure of guardianship or curators  Control group selection criteria:  Inclusion Criteria:  No diagnosed neurological pathology ≥18 years of age and ≤75 years of age Patient affiliated with a social security plan Informed consent signed by the participant  Exclusion Criteria:  Pregnant or breastfeeding woman Treatment likely to have a neuroprotective effect Any eye drops or treatments that may interfere with tear production Lens wearer Eye surgery ≤3 months Any ocular pathology except ametropia, oculomotor disorder, amblyopia Any general pathology with ocular repercussions Protective measure of guardianship or curator