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.

Riboflavin/Ultraviolet A corneal collagen cross-linking for the treatment of keratoconus: visual outcomes and Scheimpflug analysis.

PURPOSE: To evaluate the safety and efficacy of corneal collagen cross-linking (CXL) by riboflavin/UV light for the treatment of keratoconus. METHODS: This randomized, prospective, and comparative study involved 10 eyes with keratoconus diagnosed between September 2006 and January 2008. Each patient underwent CXL in the keratoconus eye. Preoperative and postoperative (at 1, 3, 6, and 12 months) biomicroscopy examinations, distance uncorrected and best-corrected visual acuities, refractive error, endothelial cell counts, keratometry readings, ultrasound pachymetry, macular thickness, and Scheimpflug analyses were performed and compared. RESULTS: Mean uncorrected visual acuity was 1.18 logarithm of the minimum angle of resolution preoperatively and 0.46 logarithm of the minimum angle of resolution at 12 months postoperatively (P < 0.001). Statistically significant reductions in the mean maximum [2.66 diopter (D), P = 0.04] and minimum (1.61 D, P = 0.03) keratometry values were present at 12 months postoperatively, in addition there was a 2.25 D reduction in the mean spherical equivalent (P = 0.01). At the end of follow-up, 8 (80%) and 6 (60%) of the 10 eyes showed a decrease in the anterior and posterior elevation values, respectively, and the thinnest point of the cornea was statistically thinner by a mean of 13.4 µm (P = 0.03). No statistically significant differences were found between preoperative and postoperative endothelial cell counts and macular thicknesses. The improvements in visual acuity, keratometry readings, and spherical equivalent values occurred progressively during follow-up. CONCLUSIONS: CXL procedure is a safe treatment for keratoconus, yields good visual results, and reduces the progression of the disease, but long follow-up is necessary.