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RESEARCH PRODUCT

Femtosecond laser–assisted intrastromal corneal ring segment implantation for high astigmatism correction after penetrating keratoplasty

subject

description

PURPOSE: To assess the visual and refractive outcomes of femtosecond laser-assisted implanta- tion of Ferrara-type intrastromal corneal ring segments (ICRS) in post-penetrating keratoplasty (PKP) eyes. SETTING: Instituto OftalmolFernOviedo, 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 G 0.15 (SD) preoperatively to 0.43 G 0.28 postoperatively (P<.0001). Postoperatively, the UDVA was 20/40 or better in 40.6% of eyes. The mean CDVA was 0.67 G 0.22 preoperatively and 0.80 G 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.