Keratoconus is an ectatic disease that touch more than 1/2000 person, it is more frequent than we expect. Treatments of this disease are in perpetual development, cross linking, rigid contact lenses, intra corneal ring segments, topoguided surface ablation, intra_ocular phakic lenses, keratoplasty. The place of intra corneal rings segments is large because of its good results in visual rehabilitation and reducing handicap in a young population. The technique of implantation is easier with femto second laser tunnel, but the challenge is the calculation of the right ring, in the right place for the right patient. This course will discuss patient selection for implantation of segments, and how to determinate the protocol: axis, sphere, cylinder, nomogram , thickness and length of the ring. It will also show a series with results, before and after treatment with comparative refractions, visual acuity ant differential topography. We will focus also on complications and their management. In conclusion, intra corneal ring segment implantation in keratoconus is a very important therapeutic tool that need a good plan to have a good result.
