In situ monitoring of laser modification process in human cataractous lensand porcine cornea using coherence tomography

We demonstrate that optical coherence tomography (OCT) is a convenient diag nostic tool to monitor pulse-to-pulse kinetics in laser interactions with b iological tissue.-ln experiments on laser modification and ablation of the cataractous human lens and the porcine cornea we have applied this techniqu e in sih to investigate different modes of preablation tissue swelling, cra ter formation and thermally affected zone development. The cataractous lens is an example of highly scattering media whereas the cornea is initially l ow scattering. The radiation with different wavelengths has been employed i ncluding that of a YAG:Er laser (lambda = 2.94 mu m), a glass:Er laser (lam bda = 1.54 mu m), YAG:Nd lasers (lambda = 1.32 mu m and lambda = 1.44 mu m) , as well as of the fifth harmonic of a Nd:YAP laser (lambda = 0.216 mu m). Pulse-to-pulse OCT monitoring has been accompanied by the probe beam shiel ding diagnostics to provide the time-resolved observation of the interactio n dynamics. (C) 1999 Society of Photo-Optical Instrumentation Engineers. [S 1083-3668(99)00801-1].