Prospective Study of Corneal Collagen Cross-linking Efficacy and Tolerance in the Treatment of Keratoconus and Corneal Ectasia: 3-Year Results

Purpose: To assess the efficacy and tolerance of corneal collagen cross-linking with corneal epithelium debridement in the stabilizing treatment of primary or secondary corneal ectasia. Methods: Prospective, comparative, single-center study of patients presenting with progressive primary or secondary corneal ectasia. The control group, comprising the fellow eye of patients with bilateral involvement, was followed up for 6 months and then treated. The parameters examined were the biomicroscopic examination, visual acuity [best spectacle-corrected visual acuity (BSCVA) and uncorrected visual acuity (UCVA)], keratometry of the central 3 mm, intraocular pressure, central pachymetry, endothelial density, and macular profile. Results: Fifty-five eyes of 39 patients were treated; the mean follow-up period was 20.8 +/- 6.8 months (range, 12-36 months). The control group comprised 16 eyes. UCVA and BSCVA were significantly improved between 3 and 12 months, reaching their minimum at 6 months, varying from 0.12 UCVA to 0.07 BSCVA (P < 0.05). These values and the keratometry values did not vary significantly after 36 months of follow-up. In contrast, analysis of the control group revealed significant keratometric deterioration of + 1.2 diopters at 6 months (P < 0.05), with no further significant variation after treatment. Analysis of the subgroups of patients with post-laser in situ keratomileusis ectasia confirmed these results. At the end of the study, intraocular pressure, pachymetry, and endothelial density were not significantly modified, and no macular profile modification was observed. Conclusion: This study shows that corneal collagen cross-linking can stabilize progressive corneal ectasia, both primary and secondary, with no induced iatrogenic effects.