Delayed Late-Onset Severe Progressive Corneal Flattening: A Complication 9 Years After Corneal Collagen Crosslinking

We describe a case of late visual deterioration with marked progressive corneal flattening 9 years after crosslinking (CXL) was performed using the Dresden protocol.

This patient with bilateral keratoconus underwent epithelium off crosslinking of the left eye only in 2007. After almost a decade of stability, he developed significant progressive corneal flattening with Descemet and stromal folds without inflammation, and a large hyperopic shift. Confocal microscopy showed keratocyte and sub-basal nerve plexus drop out. The fellow untreated eye was completely normal.

Late-onset complications of CXL are rare, and this case represents an unusually delayed long-term complication. This rare anomaly does raise awareness of the long-term potential for complications after corneal CXL.