At present, patients with keratoconus have new therapeutic options, being the intracorneal ring segments (ICRS) implants very useful for both tectonic and refractive improvement. There is a wide variety of options according to thickness, shape, arc and also to the possibility of the implantation site and the combination with other procedures, such as crosslinking. When the diversity of stages and patterns of corneal manifestation of keratoconus is added to the above options, we find that the variables and confusing factors for understanding the results, increase. In turn, other items are added that will result in a greater dispersion of results, such as the way in performing the procedure, and especially the various methods to evaluate the changes produced in the cornea by the ICRS. Also, many articles do not express a criterion of success, so we propose at least one of the following: 1. Decrease in astigmatism without rotation of the pre-existing axis, 2. Improvement of visual acuity without correction, and 3. Corrections of residual values with spherical, without astigmatisms. The importance of understanding and trying to predict what would be the expected changes after the implantation of different ICRS, in different stages of keratoconus, is emphasized. In conclusion, this article emphasizes the importance of understanding and recognizing the large number of pre-existing variables when designing a study in this area, so that they do not become weaknesses later, when interpreting its results.