Photorefractive keratectomy (PRK) is a laser eye surgery procedure that is carried out with the key intent to correct a patients vision. PRK permanently changes the shape of the frontal corneal tissue using an excimer laser, which is a high-precision ultraviolet chemical laser. The outer layer of the cornea (epithelium) is removed, and then a small amount of the corneal tissue is burnt off using the laser. Such an ablation renders the desired shape to the cornea and allows for optimal refraction.
PRK is a technologically advanced surgical procedure. For instance, a computer system tracks the eye position around 4,000 times per second, redirecting laser pulses for precise ablation. As mentioned above, the epithelium is removed prior to ablation. This does not hamper the patients vision, since the epithelium is a soft and regenerating layer, which is capable of completely replacing itself within a matter of days. However, the deeper layers, once burnt off, will remain that way because they possess limited regenerative capability. This theory is the cornerstone of the Photorefractive keratectomy surgical procedure.
PRK differs from LASIK in a way that the epithelium...