Refractive outcome and prognostic factors for success of intracorneal ring segment implantation in keratoconus: A retrospective study of 75 eyes

To define the prognostic factors for success and to evaluate the predictability of intracorneal ring segments (ICRS) in the treatment of keratoconus. In this retrospective study conducted at the University Hospital of Nantes, Keraring ICRS were implanted in 75 eyes of 65 patients with keratoconus. Best spectacle corrected visual acuity (BSCVA), manifest refraction and corneal topography were analysed. To define prognostic factors, we compared the results of 2 groups: "IMP" (gain of at least 2 lines of BSCVA) and "ROS" (the others). We evaluated the predictability of the nomogram with a mathematical model proposed by Pena-Garcia et al. (IOVS 2012). At 3 months, BSCVA improved from 0.3 to 0.2 logMAR (P