Intrastromal corneal ring segment implantation to correct astigmatism after penetrating keratoplasty

PURPOSE: To evaluate the clinical outcomes of implantation of Ferrara intrastromal corneal ring segments (ICRS) in patients with astigmatism after penetrating keratoplasty (PKP). SETTING: Private clinic, Belo Horizonte, Brazil. DESIGN: Retrospective consecutive case series. METHODS: Chart records of post-PKP patients who had ICRS implantation from May 2005 to September 2009 were retrospectively reviewed. The following parameters were studied: corrected distance visual acuity (CDVA), keratometry (K) values, spherical equivalent (SE), spherical refractive error, corneal topographic astigmatism, minimum K, and maximum K. RESULTS: The study evaluated 59 eyes (54 patients). The mean CDVA (logMAR) improved from 0.45 +/- 0.17 (SD) (range 0.18 to 1.00) to 0.30 +/- 0.17 (range 0.00 to 1.00). The mean SE was -6.34 +/- 3.40 diopters (D) (range 0.37 to -16.50 D) preoperatively and -2.66 +/- 2.52 D (range 0.87 to -10.50 D) postoperatively. The mean spherical refractive error decreased from -7.10 +/- 3.07 D (range 2.15 to 16.68 D) preoperatively to -3.46 +/- 2.05 D (range 0.88 to 10.79 D) postoperatively. No patient lost visual acuity. The mean corneal topographic astigmatism decreased from 3.37 +/- 1.51 D preoperatively to 1.69 +/- 1.04 D postoperatively. The mean maximum K value decreased from 48.09 +/- 2.56 D to 44.17 +/- 2.67 D and the mean minimum K value, from 44.90 +/- 2.54 D to 42.46 +/- 2.63 D. All changes were statistically significant (P<.0001). CONCLUSION: Intrastromal corneal ring segments effectively reduced corneal cylinder in patients with astigmatism after PKP.