Common laser procedures
The two types of Excimer laser surgery performed commonly in Canada are PRK (Photo-Refractive Keractectomy), first introduced in the early nineties, and LASIK (Laser Assisted in situ Keratomileusis), introduced in the mid-nineties. There are also more recent procedures called LASEK (Laser Epithelial Keratomileusis) and -ILASIK.
PRK: The surgeon removes the outer layer of the cornea (epithelium) with a surgical blade or blunt instrument. The laser beam, guided by a computer, is then used to vaporize tiny amounts of tissue under the surface of the cornea. The procedure removes just enough tissue to reshape the cornea in a way that corrects vision. The initial healing process is complete in about a week.
LASIK: This surgery is more complicated. The surgeon first cuts a flap in the cornea with a very sharp blade called a microkeratome, and then lifts this flap and uses a computer-guided laser to remove calculated amounts of tissue from the inside layers of the cornea bed. Afterwards, the flap is put back and the eye heals much more quickly than with PRK.
A recent advance in LASIK surgery is the use of Wavefront technology, which creates a detailed map of the eye. This helps the surgeon make even more precise correction to vision. Your eye surgeon can advise whether this is an option for you.
ILASIK: This is a modified LASIK in which the outer layer of the cornea is removed to form a flap . Another laser is then used to generate the visual correction using Wavefront technology. This procedure is used at the leading eye institutes including Duke University Medical School, the Wilmer Eye Institute at Johns Hopkins, the Bascom Palmer Eye Institute at University of Miami, and Stanford University.
LASEK: This is a variation of PRK and LASIK. The surgeon cuts the outer layer of the cornea (epithelium) with a fine blade, and uses alcohol to loosen and lift it in a single layer. The laser beam is then directed at tissue under the epithelium, as with PRK. When the laser procedure is finished, the epithelium is put back in place. LASEK is best suited to vision problems that require minor correction. The healing process takes about two weeks.