Quantitation of corneal ablation by ultraviolet laser light

A surgical role has been suggested for the excimer laser. This followed the discovery of precision etching of biological materials by the laser's ultraviolet emissions. In studying the amount of tissue removed as the laser energy density (irradiance) was varied, we found significant differences for the 193-, 249-, and 308-nm laser emission lines. The most efficient cutting irradiance for each pulse appeared to be about 200 millijoules/sq cm for 193 nm, 1,000 millijoules/sq cm for 249 nm, and 1,500 millijoules/sq cm for 308 nm. The flat slope of the etch depth curve for 193 nm suggests it will be a stable frequency when used clinically.