Risk Factors and Progression of Keratoconus

Primary objective : Description of keratoconus at baseline and during progression in 200 participants followed by the ophthalmology departments of CHU Montpellier, CHU Bordeaux and CHU Toulouse during a 2-year period. Clinical outcome, histology of the cornea and tears proteomics will be assessed in 4 groups at different points in time: * At 6 months in participants with no intervention (risk reduction instructions: not to rub their eyes) * At 6 months in participants with no intervention that didn't comply with the risk reduction instructions * At 1 month in participants assigned to cross-linking surgery * At 1 month in participants assigned to intra corneal ring surgery If both eyes are affected, both will be evaluated with their own visit agenda. Visits for no surgery participants will be set at 6 months, 12 months and 24 months in the absence of intervention (apart from the behavioral risk reduction). Visits for surgery participants will be set at D7, 1 month, 6 months, 12 months and 24 months after the procedure: cross-linking or placement of the intra corneal ring. Secondary objective : Description of the association between clinical outcomes, histological progression of the cornea and tears proteomics in time, 2 years period. Comparison of tears proteomics in 36 participants with keratoconus followed at CHU of Montpellier and healthy participants at baseline .