Clinical Outcomes of Femtosecond Laser–Assisted Implantation of Asymmetric ICRS in Keratoconus With No Coincidence of Topographic and Comatic Axes

PURPOSE: To analyze the clinical outcomes obtained with asymmetric intracorneal corneal ring segments (ICRS) of variable thickness and width in patients with keratoconus, identifying predictive parameters of the final visual outcome. METHODS: This prospective, longitudinal, non-comparative clinical trial enrolled 35 eyes of 27 patients with keratoconus with a significant difference among corneal topographic and comatic axes. All eyes underwent implantation of AJL-pro+ ICRS (AJL Ophthalmic). Visual, refractive, corneal topographic and aberrometric, and pachymetric changes were evaluated during a 3-month follow-up. RESULTS: Significant changes were detected at 3 months after surgery in manifest sphere and cylinder, spherical equivalent, overall blur strength, and corrected distance visual acuity (CDVA) ( P < .001). No losses of two or more lines of CDVA were observed, whereas 94.3% (33) of eyes gained one or more lines of CDVA. Keratometric readings and the magnitude of anterior corneal astigmatism were significantly reduced with surgery ( P < .001), as well as the levels of corneal coma ( P < .001) and spherical aberration ( P = .007). Likewise, a significant change toward less prolateness was observed ( P < .001). Significant correlations were found among the change in CDVA and preoperative CDVA ( r = −0.532, P = .001), and between the change in primary coma root mean square and the preoperative level of spherical aberration ( r = −0.542, P = .001) and coma root mean square ( r = −0.719, P < .001). CONCLUSIONS: The implantation of the ICRS evaluated in keratoconus with no coincidence between topographic and comatic axes regularizes the corneal shape and reduces the level of higher order aberrations, inducing a significant visual improvement. [ J Refract Surg . 2021;37(10):693–699.]