Atomic force microscopy and transmission electron microscopy analyses of low-temperature laser welding of the cornea

Low-temperature laser welding of the cornea is atechnique used to facilitate the closure of corneal cuts. Theprocedure consists of staining the wound with a chromophore(indocyanine green), followed by continuous waveirradiation with an 810 nm diode laser operated at lowpower densities (12 16 W/cm2), which induces localheating in the 55 65 °C range. In this study, we aimed toinvestigate the ultrastructural modifications in the extracellularmatrix following laser welding of corneal wounds bymeans of atomic force microscopy and transmission electronmicroscopy. The results evidenced marked disorganizationof the normal fibrillar assembly, although collagen appearednot to be denatured under the operating conditions weemployed. The mechanism of low-temperature laser weldingmay be related to some structural modifications of thenonfibrillar extracellular components of the corneal stroma.