Femtosecond laser-assisted intrastromal corneal ring segment implantation for high astigmatism correction after penetrating keratoplasty. J Cataract Refract Surg. 2013 Nov;39(11):1660-7. doi: 10.1016/j.jcrs.2013.04.038. Epub 2013 Sep 4.
Lisa C1, García-Fernández M, Madrid-Costa D, Torquetti L, Merayo-Lloves J, Alfonso JF. Author information: 1From the Instituto Oftalmológico Fernández-Vega (Lisa, García-Fernández, Merayo-Lloves, Alfonso), the Surgery Department (Merayo-Lloves, Alfonso), School of Medicine, University of Oviedo, Oviedo, and the Optics Department (Madrid-Costa), Faculty of Physics, University of Valencia, Spain; the Brazilian Study Group of Artificial Intelligence and Cornea (Torquetti), Brazil.
Abstract PURPOSE: To assess the visual and refractive outcomes of femtosecond laser-assisted implantation of Ferrara-type intrastromal corneal ring segments (ICRS) in post-penetrating keratoplasty (PKP) eyes.
SETTING: Instituto Oftalmológico Fernández-Vega, Oviedo, Spain.
DESIGN: Cohort study.
METHODS: Patients with previous PKP had ICRS implantation after femtosecond laser tunnel creation. The uncorrected (UDVA) and corrected (CDVA) distance visual acuities and residual refractive errors were recorded before and 6 months after ICRS implantation. The power vector method was used to analyze refractive errors preoperatively and postoperatively.
RESULTS: This study enrolled 32 eyes of 30 patients. The mean UDVA (Snellen decimal) changed from 0.16 ± 0.15 (SD) preoperatively to 0.43 ± 0.28 postoperatively (P<.0001). Postoperatively, the UDVA was 20/40 or better in 40.6% of eyes. The mean CDVA was 0.67 ± 0.22 preoperatively and 0.80 ± 0.19 postoperatively (P<.0001). Postoperatively, the CDVA was better than 20/40 in 96.9% of eyes and 20/25 or better in 56.2% of eyes. By 6 months postoperatively, no eye had lost more than 2 lines of CDVA, 4 eyes lost 1 line, 6 eyes had no change, 9 eyes gained 1 line, and 13 eyes gained 2 or more lines. The safety index at 6 months was 1.20. The spherical equivalent and astigmatism components were significantly reduced after ICRS implantation (P<.04).
CONCLUSION: Intrastromal corneal ring segment implantation using the femtosecond laser may be a good alternative for high astigmatism correction in post-PKP eyes. Copyright © 2013 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved. PMID: 24011932 [PubMed - indexed for MEDLINE]