Corrective Eye Surgeries

If you don’t like wearing glasses or contact lenses, then you may want to opt for refractive surgery, which corrects refractive errors by changing the focus of the eye (Credit: notsogoodphotography)

If you don’t like wearing glasses or contact lenses, then you may want to opt for refractive surgery, which corrects refractive errors by changing the focus of the eye. Some of the common refractive surgeries, such as photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK)  do this by reshaping the curve of the cornea to move the point at which light is focused onto the retina.

There are four categories of refractive surgery procedures – excimer laser, implant, thermal and other refractive procedures. In PRK, an excimer laser capable of removing precise amounts of tissue with micron accuracy is used to reshape the central cornea-to flatten it to correct myopia, or to make it more steep to correct hyperopia. PRK can also be used to correct astigmatism. The layer of cells covering the cornea, the epithelium, is removed, and the laser sculpts the cornea to correct the refractive error. A bandage contact lens is placed over the eye after the refractive surgery to speed the epithelial healing process.

LASIK is another vision correction procedure, which is carried out using a surgical knife, called a microkeratome, to create a hinged flap on the surface, fold it over to sculpt the underlying cornea into a new shape, and fold it back onto the cornea.

The advantages of LASIK include a quicker visual rehabilitation, reduced pain and discomfort, and the surgeon’s ability to treat higher levels of refractive error without the limitations associated with PRK.

Laser Epithelial Keratomileusis, or LASEK, a variation of LASIK, corrects myopia, hyperopia and astigmatism. The epithelium or outer surface of the cornea, is loosened with alcohol, and then peeled back to expose the cornea. The same excimer laser used in LASIK is applied to the surface of the cornea. The epithelium is placed back into position and a bandage contact lens is placed on the eye to promote healing.