Radial Keratotomy or RK and Photorefractive Keratectomy
Curious about RK?
You've probably heard RK mentioned as an alternative to conventional laser eye surgery. Along with Radial Keratotomy or RK; Photorefractive Keratectomy or PRK are also used to reshape the cornea.
In RK, a very sharp knife is used to cut slits in the cornea changing its shape. The process is fast and simple.
PRK was the first surgical procedure developed to reshape the cornea, by sculpting, using a laser.
Both of these methods predate conventional LASIK. The major difference between the two surgeries is the way that the stroma, the middle layer of the cornea, is exposed before it is vaporized with the laser. In PRK, the top layer of the cornea, called the epithelium, is scraped away to expose the stromal layer underneath. In LASIK, a flap is cut in the stromal layer and the flap is folded back.
Another type and lesser used refractive surgery is thermokeratoplasty in which heat is used to reshape the cornea. The source of the heat can be a laser, but it is a different kind of laser than is used for LASIK and PRK. Instead of a beam of concentrated light, the heat is used in the same manner. A device, either a corneal ring segment or special contact lens; are inserted into the stroma to temporarily reshape the cornea.