One-year follow-up of corneal confocal microscopy after corneal cross-linking in patients with post laser in situ keratosmileusis ectasia and keratoconus

Am J Ophthalmol. 2009 May;147(5):774-8, 778.e1. doi: 10.1016/j.ajo.2008.11.017. Epub 2009 Feb 5.

Abstract

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 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 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 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.

Publication types

  • Comparative Study

MeSH terms

  • Collagen / metabolism*
  • Corneal Stroma / metabolism
  • Corneal Stroma / pathology*
  • Dilatation, Pathologic / diagnosis
  • Dilatation, Pathologic / drug therapy
  • Dilatation, Pathologic / etiology
  • Dilatation, Pathologic / metabolism
  • Follow-Up Studies
  • Humans
  • Iatrogenic Disease
  • Keratoconus / diagnosis*
  • Keratoconus / drug therapy
  • Keratoconus / etiology
  • Keratoconus / metabolism
  • Keratomileusis, Laser In Situ / adverse effects*
  • Microscopy, Confocal*
  • Photochemotherapy*
  • Photosensitizing Agents / therapeutic use
  • Postoperative Complications*
  • Prospective Studies
  • Riboflavin / therapeutic use
  • Ultraviolet Rays

Substances

  • Photosensitizing Agents
  • Collagen
  • Riboflavin