One-Year Follow-up of Corneal Confocal MicroscopyAfter Corneal Cross-Linking in Patients With Post LaserIn Situ Keratosmileusis Ectasia and Keratoconus

摘要

PURPOSE: To investigate corneal tissue alterations after corneal collagen cross-linking in patients with post laser in situ keratosmileusis (LASIK) keratectasia and keratoconus.;DESIGN: Prospective comparative case series.;METHODS: Five patients (5 eyes) with iatrogenic keratectasia after LASIK and 5 patients (5 eyes) with progressive keratoconus were included. All eyes underwent corneal cross-linking and were assessed by corneal in vivo confocal microscopy. Three normal/healthy and 3 post-LASIK without ectasia corneas were also examined as controls.;RESULTS: All corneas revealed normal epithelial thickness before and after surgery. Images of both keratoconic and post-LASIK corneal ectasia eyes revealed similar morphologic alterations. The subepithelial nerve plexus was absent immediately after treatment; regeneration of nerves was evident after the third postoperative month. Keratocytes were absent from the anterior 300 mum of the stroma in the first 3 months while the posterior stromal density of keratocytes was increased. Corneal collagen fibers in the anterior stroma were distributed unevenly in a net-like formation. Full-thickness keratocyte repopula-tion in the anterior and mid-corneal stroma was detected 6 months after treatment. The corneal endothelium did not undergo any significant changes, since the cell density and hexagonality was not found altered during the follow-up period.;CONCLUSIONS: Keratocyte nuclei apoptosis in the anterior and intermediate corneal stroma along with collagen alterations were observed during the first 3 postcornealcross-linking months. Gradual keratocyte repopulation was demonstrated over the following months. Corneal alterations after corneal cross-linking were similar in both keratoconic and post-LASIK corneal ectasia eyes.