Intrastromal Corneal Ring Segments Implantation After Deep Anterior Lamellar Keratoplasty for Astigmatism Correction: Mid-term and Long-term Follow-up

Purpose:The aim of this study was to assess the long-term outcomes of implanting intrastromal corneal ring segments (ICRSs) using a femtosecond laser for correcting astigmatism in patients who had previous deep anterior lamellar keratoplasty (DALK) throughout a 5-year follow-up period.Methods:This retrospective study included 40 eyes of 40 patients with previous DALK and astigmatism & GE;3.00 D who underwent Ferrara-type ICRS implantation. The manifest refraction, uncorrected (UDVA) and corrected (CDVA) distance visual acuity (logMAR), and corneal topography were recorded preoperatively and at 6, 12, 36, and 60 months postoperatively.Results:The mean UDVA (logMAR scale) improved from 1.39 & PLUSMN; 0.55 preoperatively to 0.71 & PLUSMN; 0.37 at 6 months postoperatively (P < 0.0001). The mean CDVA (logMAR) significantly improved from 0.36 & PLUSMN; 0.17 to 0.22 & PLUSMN; 0.12 at 6 months after surgery (P < 0.0001). Both UDVA and CDVA remained unchanged throughout the follow-up (P = 0.09). Postoperatively, no eyes lost lines of CDVA compared to preoperatively, and around 80% of the eyes gained lines of CDVA. The safety index remained stable at a value of 1.4 throughout the follow-up. The refractive cylinder decreased from -6.86 & PLUSMN; 2.62 D preoperatively to -2.33 & PLUSMN; 1.09D at 6 months postoperatively (P < 0.0001), and subsequently, it was stable over the postoperative period (P = 0.2). The maximum and minimum keratometry measurements significantly decreased after surgery and remained stable over the postoperative follow-up period (P > 0.07).Conclusions:This study shows the long-term viability of Ferrara-type ICRS implantation using a femtosecond laser as a surgical alternative for astigmatism correction in post-DALK eyes.