Corneal ablation using newly–developed 193nm solid state laser: A preliminary experiment

Abstract

Abstract: : Purpose: The argon fluoride excimer laser has been playing one of the most important roles in the refractive surgery. To improve the clinical results of current photorefractive surgery, however, alternative lasers might be desirable to solve the disadvantages of the excimer laser such as wide pulse duration, low repetition rate, potential toxic gas exposure, and difficulties in beam homogenization or power stabilization. As we have developed a 193nm all solid state laser previously (Conference on Lasers and Electro–Optics, 2003), the first corneal ablation was conducted with the laser in this study. Methods: A prototype laser engine was developed by the combination of 1547nm laser diode, fiber amplifiers, and five stages of frequency–conversion system using CLBO crystal as the last stage. PMMA plates were ablated with the prototype laser and the ArF excimer laser to know the relationships between fluence and ablation rate. Light microscopic and scanning electron microscopic examinations were performed with pig corneas to investigate the nature of the ablated corneal surface. Results: The relationship between fluence and ablation rate in the 193nm solid state laser was resembled to that in the ArF excimer laser. Light or scanning electron microscopy of the pig corneal stroma showed smooth linear or square ablations with the condition of 10 kHz and 3mW. Conclusions: Corneal ablation can be performed by our newly–developed laser. It might be worth to conduct further investigations with this laser as one of the possible alternative laser sources for the keratorefractive surgery.

Keywords: laser • refractive surgery • pathology: experimental