Photorefractive keratectomy: A technique for laser refractive surgery

TLDR

The excimer laser offers entirely new corneal surgery procedures. The study describes photorefractive keratectomy, a procedure reshaping the cornea's central optical zone via far‑ultraviolet tissue ablation, and presents equations for the required ablation to achieve desired refractive corrections. The authors present equations for the required tissue ablation and describe conditions for beam uniformity, demonstrating a method of improving uniformity via beam integration by rotation. In rabbit corneas, healing after area ablation was observed, with deep cuts showing irregular surface quality after five days while shallow cuts produced more regular results, consistent with the predicted beam characteristics.

Abstract

The excimer laser offers entirely new corneal surgery procedures. In this paper, we describe conditions for one such procedure, photorefractive keratectomy, the direct reshaping of the cornea's central optical zone using tissue ablation with far ultraviolet radiation. We present equations for the required tissue ablation to achieve required refractive corrections. Conditions for beam uniformity are presented and a method of achieving better beam uniformity using beam integration by rotation is demonstrated. The healing of rabbit corneas after area ablation was observed. Five days after treatment, the surface quality of deep cuts was very irregular; the shallow cuts produced more regular results, as predicted by our calculations of beam characteristics.