Asymmetric Intracorneal Ring Segment Implantation in Snowman-Phenotype Keratoconus – Study Summary
This retrospective interventional study evaluated the refractive, aberrometric, topographic and topometric outcomes of asymmetric intracorneal ring segment (ICRS) implantation in cases of snowman-phenotype (asymmetric bow-tie) keratoconus.
Following the creation of corneal tunnels with the aid of a femtosecond laser, two asymmetric ICRS (Keraring AS) were placed in each eye. Over a mean follow-up of 11 months, visual acuity, refraction values, corneal curvature measurements, aberrations and corneal irregularity indices were compared before and after surgery.
In the 71 eyes included in the study, a significant reduction in spherical and cylindrical refractive errors and a marked increase in uncorrected and corrected visual acuity were found after asymmetric ICRS implantation. Corneal steepening, astigmatism, asphericity (Q value) and, in particular, vertical coma aberration decreased significantly. Statistically significant improvement was also observed in all topometric indices indicating corneal irregularity.
In conclusion, asymmetric intracorneal ring segment implantation stands out as an effective and safe surgical treatment option that improves visual quality and corneal regularity in snowman-phenotype keratoconus.
Prof. Dr. Efekan Coşkunseven