Conservative treatment of keratoconus by riboflavin-UVA-induced cross-linking of corneal collagen: Qualitative investigation of corneal epithelium and subepithelial nerve plexus regeneration by in vivo H RT II system confocal microscopy in humans

PU R P O S E. To assess corneal tissue modifications after riboflavin-UVA-induced cross-linking of c o rneal collagen in patients with progressive keratoconus as well as regeneration of epithelium and subepithelial nerve plexus by in vivo H RT II system confocal microscopy in humans. ME T H O D S. Ten patients with progressive keratoconus were treated by riboflavin-UVA i n d u c e d cross-linking of corneal collagen, involving assessment of ultrastructural modifications of the corneal epithelium and subepithelial nerve plexus by HRT II system confocal microscopy. Treatment included instillation of 0.1% riboflavin–20% dextrane solution 5 minutes before U VA irradiation and every 5 minutes for a total of 30 minutes. Radiant energy was 3 mW/cm2 or 5.4 Joule/cm2 and the source was dual UVA (370 nm) light-emitting led. The protocol included the operation followed by antibiotic medication and eye dressing with a soft therapeutic contact lens. Changes in epithelium and subepithelial and stromal nerve plexus were assessed by HRT II system confocal microscopy in vivo. RE S U LT S. After 5 days of soft contact lens wearing corneal epithelium has a regular morphology and density. Disappearance of subepithelial stromal nerve fibers was observed in the central irradiated area where, 1 month after the operation, initial re i n n e rvation was microscopically observed. No changes in nerve fibers were observed in the peripheral unt reated with a clear lateral transition between the two areas. Six months after the operation, the anterior subepithelial stroma was recolonized by nerve fibers with restoration of c o rneal sensitivity. CO N C L U S I O N S. HRT II system confocal microscopy confirms corneal epithelium re s t o re and re i n n e rvation after riboflavin-UVA-induced collagen cross-linking directly in vivo in humans. (Eur J Ophthalmol 2006; 16: 5 3 05 )