Comparison of Visual, Refractive and Aberration Measurements of INTACS versus Tricyclic ICL Lens Implantation; A Four-year Follow-up

Abstract This study was performed to evaluate the visual, refractive, and aberration measurement results of ۲ implants, including Intacs Intracorneal Ring Segments (ICRS) and phakic Toric Implantable Collamer Lens (TICL), in patients with moderate Keratoconus (KCN). In this retrospective cross-sectional study, ۳۰ patients with KCN with a mean age of ۲۹.۸۳ years were included in ۲ groups, including the Intacs Intracorneal Ring Segments (ICRS) group and the phakic Toric Implantable Collamer Lens (TICL) group. Preoperative data as well as ۶-month, ۱-, ۲-, ۳- and ۴-year follow-up data after the operation were collected and analyzed with the SPSS software (ver. ۲۳.۰, SPSS, Inc., Chicago, IL), using the paired t-test, independent t-test, repeated measures Analysis of Variance (ANOVA), and one-way ANOVA. This study included ۳۰ patients with KCN with a mean age of ۲۹.۸۳ years and range of ۲۵ to ۳۵ years, including ۱۷ males with a mean age of ۳۰.۱۱ years and ۱۳ female with a mean age of ۲۹.۲۵ years. Except for preoperative Uncorrected Distance Visual Acuity (UCDVA), Spherical Equivalent (SE) and astigmatism, there was a significant difference between the ۲ groups regarding other variables. The TICL group had a significantly better UCDVA and Best Corrected Distance Visual Acuity (BCDVA) in all post-operative follow-ups, and SE and astigmatism values were significantly lower in all post-operative follow-ups when compared with the ICRS group. There was a significant reduction in corneal and total coma as well as internal trefoil aberrations (P<۰.۰۱, P<۰.۰۱, and P=۰.۰۱۴, respectively) in the ICRS group, and TICL led to a significant reduction in internal trefoil aberration with P<۰.۰۳. Comparison of the ۲ groups revealed a significant difference in corneal spherical (P<۰.۰۱) and total coma (P=۰.۰۲) aberrations and no significant differences in other HOA. Both ICRS and TICL are useful in patients with moderate KCN. However, TICL appears to have more stable and predictable vision results.Â