Collagen structural changes following riboflavin and UV-collagen cross-linking have been observed in vitro using second-harmonic generation microscopy, in a collaborative work with LOUM (Juan Manuel Bueno and Pablo Artal) from the Universidad de Murcia. The results are published in Bueno et al. Multiphoton Microscopy of Ex-Vivo Corneas After Collagen Cross-Linking. Invest. Ophthalmol. Vis. Sci. July 2011, Vol. 52, No. 8