Investigation of Corneal Alterations With in vivo Confocal Microscopy After Corneal Collagen Cross-Linking Using Riboflavin and UVA-Treatment in Patients With Progressive Keratoconus

Abstract

Purpose:: The keratoconus is a corneal degeneration with a mainly bilateral manifestation. It is characterized by a thinning of the central cornea which leads to a progressive visual loss. Until now a perforating keratoplastic was the only therapy option in advanced cases. A new therapeutically technique for treating progressive keratoconus is the so-called corneal collagen cross-linking. It has shown to increase effectively the biomechanical strength of the cornea and to stop or even reverse the progression of keratoconus. The aim of the study was to investigate cornea alterations induced by the corneal cross-linking therapy.

Methods:: A series of patients (5 eyes) with progressive keratoconus were treated with the corneal collagen cross-linking using Riboflavin and UVA-irradiation. Before and after this cross-linking treatment patients underwent a slitlamp microscopy, cornea topography as well as an in vivo laser scanning microscopy (Heidelberg Retina Tomograpgh II in combination with the Rostock Cornea Module). The follow-up of the patients was 6 months.

Results:: Complete regeneration of corneal epithelium was noted in 1 week without signs of edema. There were no signs of presence of subepithelial nerve plexus at the level of Bowman’s membrane. Rarefaction of keratocytes with a honeycomb-like lacunar edema appeared direct after the treatment and the typical physiological keratocyte network with regular structure of stromal nerve fibres was found in 6 months after the surgery. The endothelium showed a regular cell density and morphology even after the cross-linking therapy.

Conclusions:: The confocal in vivo laser scanning microscopy is an easy and reliable technique to present corneal alterations after corneal collagen cross-linking using Riboflavin and UVA-irradiation. It allows to get a repeatable data about the alterations of epithelial and corneal structures direct after the surgery as well as to determine the time of complete physiological recovery of the cornea. These might be a novel aspect in the postoperative care by this group of patients.

Keywords: cornea: stroma and keratocytes • keratoconus • microscopy: confocal/tunneling