Evaluation of a comatic aberration-based nomogram for symmetrical intracorneal ring segment implantation in keratoconus.

OBJECTIVE

The aim of this study was to evaluate the short-term results of a comatic aberration-based nomogram of intrastromal corneal ring segments in different keratoconus patterns and stages.

SETTING

Hospital Foundation Adolphe de Rothschild-Noémie de Rothschild Institute.

DESIGN

A retrospective observational single-center study.

METHODS

This study includes patients who underwent intracorneal ring segment implantation with Kc Solutions rings from January 2018 to December 2022. A complete ocular examination was performed preoperatively: uncorrected (UDVA) and best-corrected distance visual acuity (CDVA), slit lamp anterior segment, and fundus examination. Corneal topography was performed with the Pentacam HR system.

RESULTS

Ninety-one eyes of 68 patients were included. Both UDVA and CDVA improved significantly from 0.47 ± 0.23 logMAR and 0.39 ± 0.25 logMAR at baseline to 0.34 ± 0.32 logMAR and 0.17 ± 0.19 logMAR after 3 months. A significant decrease of 2.13 ± 2.44 D in cylinder and 2.12 ± 3.06 D in SE was observed (p < 0.001). The Astigmatic Index of Success (AIS) was 0.43 ± 0.49, and 49 eyes (53.8%) had a decrease in cylinder of more than 50%. The flattest (K1) and steepest (K2) meridians, and maximum keratometry (Kmax) decreased at 3 months. The y value of the steepest point showed a significant upper shift (p = 0.007). Total RMS, higher-order aberration (HOA) RMS, and comatic aberrations all decreased significantly postoperatively (p < 0.001).

CONCLUSIONS

The present study demonstrates that targeting vertical coma can reduce total RMS and HOA aberrations in addition to improving topographic and refractive outcomes.