Intraocular enhancement of pressure transients induced by argon-fluoride laser pulses during photorefractive keratectomy

Pulsed laser ablation of corneal tissue at the typical operative fluences of Argon-Fluoride photorefractive keratectomy produces stress waves propagating into the eye. Temporal and spatial evolution of these pressure pulses during propagation were measured directly in porcine eyes with a needle hydrophone. Beside diffraction effects that give rise to a bipolar shape of the pressure pulse with a positive compression peak followed by a marked rarefaction phase, we found a significant focusing of the stress wavefront caused by the spherical shape of the cornea, that increased for larger irradiation spot diameters