Gas chromatographic and mass spectroscopic analysis of excimer and erbium: yttrium aluminum garnet laser-ablated human cornea.

The photoablative products from human cadaver corneas treated with lasers were investigated using gas chromatography and mass spectroscopy. The photoablations were done separately with an excimer laser (193 nm) and with an erbium: yttrium aluminum garnet (Er:YAG) laser (2.94 microns). More than 20 different types of molecules with a molecular weight of 40-400 mass units could be identified, most of which were found to be alkanes. The comparison of the two types of laser ablations showed larger fragments and fewer types of molecules present after excimer laser treatment than after Er:YAG photoablation.