The aim of this study is to obtain an early biomarker of amyotrophic lateral sclerosis and Friedreich's Ataxia which allows to diagnose the disease in an initial stage and to follow up the patient with optic coherence tomography, a fast, non-invasive and comfortable method

All patients will be asked about their data and their general medical history, and will be underwent on one hand, a complete neurological examination including the degree of neurological impairment quantified according to the functional rating scale of ALS (ALSFRS-r) or Scale for the assessment and rating of ataxia (SARA); On the other hand, they will have a complete ophthalmological examination too, including the patient's graduation, pupillary and ocular motility examination, biomicroscopy, Goldman tonometry and fundus exam. Patients will be performed too a conventional automated Humprey perimetry, color test (Farnsworth-Munsell 28 Hue Color Vision Test) and finally an optical coherence tomography (OCT) in order to see possible anatomical alterations in both macula and optic nerve. The follow-up of these explorations will be repeated in all cases at 6 months.

Inclusion Criteria:

• Older than 18 years.
• Best corrected visual acuity more than 0.4 (20/50 Snellen = 0.4 logMAR = 65 ETDRS letters).
• Refractive defect less than 5 diopters of spherical equivalent and / or cylinder less than 2 diopters.
• Transparent optical media: Opacity of crystalline <1 according to Lens Opacities Classification System (LOCS) III.
• Open anterior chamber angle assessed by gonioscopy with Goldmann lens (grade> III).
• Availability and collaboration to carry out the tests of the exploratory protocol.
• Acceptance of informed consent.

Exclusion Criteria:

• Previous intraocular surgeries of less than 6 months of evolution. Patients with refractive surgery using the LASIK or LASEK technique will not be excluded.
• Physical or mental difficulties to perform reliable and reproducible perimeters.
• Pathology and / or ocular malformations, angular or optic nerve anomalies.
• Any retinopathy or maculopathy.
• Intraocular pressure (IOP)> 21 mmHg.
• Signal-to-noise ratio in OCT less than 5/10.
• Failure to meet any inclusion criteria.
• Mental retardation or any other limitation in obtaining informed consent.

Amyotrophic lateral sclerosis patients Friedreich's ataxia patients Healthy volunteers