One-year outcomes of intrastromal corneal ring segment implantation for the correction of high compound myopic and mixed astigmatism in healthy corneas.

INTRODUCTION AND

OBJECTIVES

To assess the outcomes of intrastromal corneal ring segment (ICRS) implantation using a femtosecond laser for the correction of high mixed or compound myopic astigmatism.

PATIENTS AND

METHODS

This retrospective study included 38 eyes from 24 patients with mixed or compound myopic astigmatism ≥4.00 D who underwent Ferrara-type ICRS implantation. Manifest refraction, uncorrected distance visual acuity (UDVA), and corrected distance visual acuity (CDVA) (logMAR), as well as corneal topography, were recorded preoperatively and at 12 months postoperatively.

RESULTS

The refractive cylinder decreased from -6.31 ± 1.69 D preoperatively to -1.57 ± 0.75 D postoperatively (P < 0.0001). In cases with mixed astigmatism, the refractive sphere decreased from +3.65 ± 2.21 D to +1.34 ± 1.70 D (P < 0.0001). By contrast, in eyes with compound myopic astigmatism, the refractive sphere increased from -3.55 ± 3.04 D to -4.31 ± 3.23 D (P = 0.003). The mean UDVA (logMAR) significantly improved from 0.90 ± 0.27 preoperatively to 0.38 ± 0.29 postoperatively (P < 0.0001). The mean CDVA (logMAR) changed from 0.10 ± 0.13 to 0.07 ± 0.08 after surgery (P = 0.008). Postoperative UDVA was significantly better in cases with mixed astigmatism compared with compound myopic astigmatism (0.31 ± 0.20 vs 0.63 ± 0.36 logMAR; P < 0.0001). However, no differences were observed in CDVA (0.06 ± 0.08 vs 0.08 ± 0.08 logMAR; P = 0.2).

CONCLUSIONS

The outcomes of this study support the viability of Ferrara-type ICRS implantation as a surgical alternative for reducing high astigmatism to low-to-moderate levels. Astigmatism reduction is accompanied by a decrease in the refractive sphere in mixed astigmatism and an increase in compound myopic astigmatism.