ferrara intrastromal corneal ring segments in keratoconus

purpose: to evaluate the efficacy and safety of ferrara intra-stromal corneal ring (fiscr) segments for keratoconus. methods: the study was performed on 57 eyes of 44 patients with keratoconus and clear cornea who were contact lens intolerant. subjects underwent complete ophthalmic examination before surgery. objective and subjective refraction achieving the best visual acuity was used to determine the refractive error and orbscan ii corneal topography system provided the corneal data on pre- and post-operative visits. fiscr segments were implanted according to the manufacturer’s monograms and standard surgical method. results: mean patients age was 26.7 ± 6.8 years. patients were followed for 2-14 months (mean, 9 months). at last follow-up visit, mean ± standard deviation improvement in main outcome measures were as follows: 5.4 ± 3.65 d for spherical equivalent (p< 0.001), 1.89 ± 2.25 d for magnitude of cylindrical error (p< 0.001), 0.61 ± 0.46 logmar for best corrected visual acuity (p<0.001), and 0.18±0.36 logmar for uncorrected visual acuity (p=0.002). the rings were removed and reimplanted in 3 cases due to inadequate depth and in one case because of suspected infectious keratitis. conclusion: implantation of fiscr segments is a safe and reversible procedure, particularly in contact-lens-intolerant patients with keratoconus whose only option is corneal transplantation.