Far‐ultraviolet laser ablation of the cornea: Photoacoustic studies

Abstract

Wide bandwidth piezoelectric transducers made of thin (9 m̈m) polyvinylidene fluoride film have been used to make time‐resolved measurements of the stress‐wave generated by far‐ultraviolet (193 nm) laser ablation in corneal tissue in vitro. At high fluence (∼ 250 mJ/cm2), ablation commences within 10 ns (± 5 ns) of the laser pulse and generates short acoustic impulses (∼ 30 ns). The time profile of the ablation, when coupled to the energy requirements for ablation from earlier work, allows the estimation of a temperature and a half‐life for the thermal decomposition of the collagen in cornea. These values do not support a photo‐thermal mechanism for the ablation under the experimental conditions. Copyright © 1987 Wiley‐Liss, Inc., A Wiley Company