One-Year Follow-up of Corneal Confocal Microscopy After Corneal Cross-Linking in Patients With Post Laser In Situ Keratosmileusis Ectasia and Keratoconus

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 thick, ness 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 mu m 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 repopulation 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 den, sity and hexagonality was not found altered during the follow-up period. CONCLUSIONS: Keratocyte nuclei apoptosis in the ante, rior and intermediate corneal stroma along with collagen alterations were observed during the first 3 postcorneal cross,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. (Am J Ophthalmol 2009;147:774-778. (c) 2009 by Elsevier Inc. All rights reserved.)