Final answer:
Pulsed laser radiation in PRK allows for precise ablation of the cornea in ultra-thin layers, enhancing accuracy and reducing thermal damage, which results in high correction success and minimizes recovery time.
Step-by-step explanation:
The use of pulsed laser radiation in PRK procedures, as opposed to continuous laser radiation, allows the cornea to be precisely ablated in extremely thin layers. This level of control is possible because the lasers used, particularly excimer lasers, emit intense light in a very pure, well-focused electromagnetic wavelength. They are well absorbed by biological tissue, which enables them to evaporate rather than burn the corneal tissue. Moreover, pulsed lasers apply bursts of energy at a rate that prevents excessive heat build-up, reducing potential thermal damage to the surrounding tissues of the cornea and enhancing the precision of the ablation.
The precisely controlled ablation is achieved by a computer-programmed series of bursts, usually at a rate of 10 per second, allowing for the correction of nearsightedness, farsightedness, and astigmatism with high accuracy. This precise application of energy ensures that normal distant vision is achieved in more than 90% of patients. The procedure is rapid, and the healing process is generally quick and nearly painless, with over 1 million Americans per year undergoing LASIK, a similar procedure.