One year results of European multicenter study of intrastromal corneal ring segments - Part 1: Refractive outcomes

Purpose: To assess the efficacy, predictability, stability, and safety of c orrecting myopia with intrastromal corneal ring segments (ICRS(R), KeraVisi on, inc.). Setting: Twelve European investigational sites. Methods: Patients with myopia of -1.0 to -6.0 diopters (D) and best spectac le-corrected visual acuity (BSCVA) of 20/20 or better (except in 3 eyes) we re assigned to receive 1 of 5 ICRS thicknesses (0.25, 0.30, 0.35, 0.40, or 0.45 mm). Efficacy was assessed by postoperative uncorrected visual acuity (UCVA), predictability of refractive outcome (deviation from predicted cycl oplegic refraction spherical equivalent), and stability of refractive effec t (manifest refraction spherical equivalent [MRSE]). Safety was assessed by maintenance or loss of preoperative BSCVA and induced manifest refraction cylinder, Measurements were made preoperatively and 1 and 7 days and 1, 2, 3, 6, and 12 months postoperatively, Results: One hundred fifty-nine ICRSs were implanted in the eyes of 107 pat ients (52 patients had bilateral implantation). Preoperatively, UCVA was wo rse than 20/40 in 98% of eyes (155/159); 12 months postoperatively, it was 20/20 or better in 63% of eyes (83/132) and 20/40 or better in 96% (127/132 ). Predicted refractive corrections for each ICRS thickness generally corre lated with achieved corrections. At 12 months postoperatively, 90% of eyes (124/138) were within +/-1.00 D of piano (MRSE). Two or more lines of BSCVA were lost in 6% of eyes (8/135); all 8 eyes had BSCVAs of 20/25 or better. Conclusion: The ICRS safely, effectively, and predictably reduced or elimin ated low to moderate myopia. Refractive correction was stable through the 1 2 month follow-up. J Cataract Refract Surg 2001; 27:277-286 (C) 2001 ASCRS and ESCRS.