Corneal surface ablation by 193 nm excimer laser and wound healing in rabbits.

The 193 nm argon fluoride excimer laser was used to ablate a 6 mm diameter area of the central rabbit cornea under various conditions of power, beam configuration and exposure time. High repetition rates or prolonged exposures produced charring and prevented rapid epithelial wound closure. Endothelial vacuolization, reduction in density, and displacement of cell material into Descemet's layer resulted in these experiments. A beam of low and uniform power intensity (40 pulses per second, 100 seconds at 23 mJ/cm2) reduced stromal damage, cellular infiltration, and epithelial irregularities including punctate staining and cell exfoliation. Epithelial rehealing occurred within two days. Basal lamina and hemidesmosomes were reformed by one week. Endothelial damage was not detected. Excimer laser ablation may allow removal of superficial dystrophies or scars, followed by rapid healing from normal corneal reparative processes.

Photometric evaluation of YAG-induced polymethylmethacrylate damage in a keratoprosthesis.

The use of the Nd:YAG laser in the photodiscission of retroprosthetic membranes represents a new clinical application. However, the potential adverse ophthalmic effects of YAG-induced PMMA damage to the keratoprosthesis are unknown. Consequently, precise photometric studies were conducted to evaluate image quality of the keratoprosthesis following YAG laser irradiation.