Corneal Collagen Cross-Linking Before Ferrara Intrastromal Corneal Ring Implantation for the Treatment of Progressive Keratoconus

PURPOSE: To evaluate the safety, efficacy, and stability of sequential corneal collagen cross-linking (CXL) and Ferrara intrastromal corneal ring segment (FR) implantation in selected patients with progressive keratoconus. METHODS: This prospective study involved 9 eyes with progressive keratoconus and a preoperative cylinder value equal to or greater than 5 diopters (D) diagnosed between June 2007 and October 2008. Preoperative and postoperative (6 months after the CXL procedure and 6 months after the FR implantation) biomicroscopy examinations, distance uncorrected and best-corrected visual acuities, refractive error, and topographic maps were evaluated and compared. RESULTS: Mean uncorrected visual acuity was 1.11 logarithm of the minimal angle of resolution (logMAR) preoperatively and 0.75 logMAR at 6 months after CXL (P = 0.03) and 0.23 logMAR at 6 months after FR implantation (P < 0.001). Mean best-corrected visual acuity was 0.26 logMAR preoperatively and 0.24 logMAR at 6 months after CXL (P = 0.87) and 0.12 logMAR at 6 months after FR (P = 0.05). Statistically significant reductions in the mean spherical equivalent (4.38 D; P < 0.001) and mean maximum (5.58 D; P < 0.001) and minimum (4.17 D; P < 0.001) keratometry values were present at 6 months after FR. CONCLUSIONS: FR implantation after CXL is a safe and efficacious treatment option for managing selected patients with progressive keratoconus. Good results in terms of visual acuity, postoperative residual refractive error, and keratometry values were obtained. Longer follow-up would be valuable to confirm the stability of these results.