Abstract

Continuous-wave (cw) and repetitively pulsed (rp) hydrogen fluoride (HF) and deuterium fluoride (DF) chemical laser interactions with human corneal tissues have been studied to determine the intrinsic ablation performance and efficiency of these candidate lasers for corneal microsurgery applications and to measure the responses and properties of corneal tissue in well-characterized laser irradiation conditions. Continuous-wave experiments were performed on corneal tissues over a broad range of intensities (3-100 kW/cm²) to determine burn-through times and measure optical properties and front and back surface temperatures during laser irradiation. Burn-through data were analyzed to provide Q* values (effective enthalpies of ablation per gram of material) as a function of laser wavelength. Optical properties of tissues were measured before (as well as during) laser irradiation. Histologic examinations of postirradiated tissues were performed to determine the spatial extent of thermal damage adjacent to ablation craters. Similar experiments were completed using rp laser irradiations as a function of wavelength, pulse waveform, and pulse fluence using a rp HF-DF chemical laser system. Figure 1 shows a schematic diagram of the rp experimental apparatus.

© 1988 Optical Society of America