[Quantitative analysis of corneal excisions using argon fluoride excimer laser (193 nanometers)]

Excimer lasers represent a new and distinctive class of laser-tissue interaction termed photoablation. They can ablate materials with a high degree of precision and minimal damage to surrounding structures. The argon Fluoride excimer laser, which offers the possibility of non-contact corneal cutting, has a potential for clinical application of keratorefractive surgery. Since each pulse of excimer laser etches some amounts of tissue from the cornea, the repetitive pulses focused to a narrow line can create linear excisions. In this study, a quantitative analysis of both depth and width of corneal excisions was made on cadaver eyes at a given fluence (600 mj/cm2) and a constant repetitive rate (20Hz). The amount of ablation per pulse was not constant and the excisional depth did not show a linear correlation with pulse numbers. Both the depth and width of transversal excisions were more homogenous than those of radial excisions along the entire length of ablation.