Quantitation of Corneal Ablation by Ultraviolet Laser Light

TLDR

The excimer laser has been proposed for surgical use following discoveries of its precise ultraviolet etching of biological tissues. The study varied laser irradiance to measure tissue removal across 193‑, 249‑, and 308‑nm emission lines. Optimal cutting irradiances were ~200 mJ/cm² for 193 nm, ~1,000 mJ/cm² for 249 nm, and ~1,500 mJ/cm² for 308 nm, with 193 nm showing a flat etch depth curve indicating clinical stability.

Abstract

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.