What is PRK?
PRK or Photorefractive Keratectomy was the first laser refractive surgery approved by the FDA. PRK has been performed for over 20 years and has a very long track record of safety. PRK differs from LASIK in that no flap of tissue is created prior to resculpting the cornea with the EXCIMER laser.
This makes PRK a good option for patients whose corneas may be too thin or who have any other problems that would render them unable to have conventional LASIK. PRK may also be a better treatment for patients with moderately dry eyes. Since PRK doesn't involve creating a corneal flap, there is quicker recovery with respect to dry eye. PRK can be used to treat nearsightedness, farsightedness, and astigmatism.
In the long run, PRK and LASIK are equivalent procedures as far as quality of vision is concerned. Studies show that 1 month after the procedure there is no difference in the quality of vision between PRK and LASIK. The primary difference between LASIK and PRK is the speed of visual recovery. PRK has a more uncomfortable recovery for the first 3 to 4 days after the procedure. However PRK has some very clear and pronounced advantages over LASIK. All of these advantages stem from the fact that PRK is more tissue sparing then LASIK.
What to Expect with PRK
During the PRK, you will be taken to the laser suite and positioned on the laser bed. Numbing drops will be instilled in you eyes so you are comfortable during the procedure. The doctor will drape your eyelashes with plastic drapes to create a sterile working environment. The top layer of the cornea, the epithelium, is gently removed to prepare the eye for treatment. Once the epithelium is removed, the EXCIMER laser is used to resculpt the cornea, reducing the refractive error in the same fashion as is done after flap creation with LASIK. Throughout the procedure anesthetic drops are used to numb the eye, making the process completely painless. Once the procedfure is done a bandage contact lens is placed on the cornea to help it heal. The fact is that the corneal epithelium is the fastest healing tissue in the body.
Figure 1: corneal topography is performed and is used to quantify the curvature of the cornea
Figure 2: demonstrates the corneal topograpical map. The map reveals the imperfections that cause nearsightedness and astigmatism.
Figure 3: epithelium or the top layer of the cornea has been cleared
Figure 4: cornea and its corresponding topography just prior to the treatment with the EXCIMER Laser
Figure 5: flying spot laser reshaping the corneal surface, removing imperfections
Figure 6: as the treatment is completed, the corneal surface is now free of imperfections that cause nearsightedness and astigmatism
After the treatment you will be discharged home, where we recommend that you rest. The post operative recovery after PRK is where the biggest difference with LASIK is noted. The recovery takes 3 to 4 days, during which patients experience varying degrees of light sensitivity, foreign body sensation, tearing and discomfort. On day 3 or 4 after the procedure the bandage contact lens is removed. At that point vision is very good. Small fluctuations in visual acuity are still possible for about a month after the procedure.
For more complete instructions on what to do before and after the procedure please click here.