Photo-Refractive Keratectomy or PRK
Photorefractive Keratectomy or PRK for short is the “original” laser vision correction procedure. The concept behind PRK drove the first wave of laser vision correction procedures in the early 1990’s. As a surgical procedure it has continue to be refined and still has a place amongst modern vision correction solutions. However despite those refinements, PRK is used much less frequently than LASIK.
PRK has primarily been used to correct error in refraction such as nearsightedness, farsightedness and astigmatism. With more advanced excimer laser systems like the AMO-VISX Star S4 IR it is also easy perform wavefront guided treatments directed at fixing both lower and higher order aberrations. From a quality of vision perspective, there is no fundamental difference in the visual results delivered by Lasik or PRK.
The primary reason why PRK is not used as frequently as Lasik is that the speed of visual recovery is very much slower and the patient has much more pain. As a result, patients must take several days off work for recovery after their surgery and their vision often can take several weeks to months to become completely clear. In addition to the slow and frequently painful recovery, PRK does exhibit a more significant risk for corneal haze or scarring in the visual axis and a higher risk for infection because the cornea is exposed to bacterial invasion for a longer period of time than with Lasik. As a result of these factors, PRK is only performed infrequently today.
PRK technique differs from LASIK in that no flap is created before applying the laser. The top layer of cells on the cornea, the epithelium, is removed manually before the laser reshapes the cornea. Once the epithelium is removed and the surface of the cornea is exposed, the photoablation process is performed to change the cornea to the new desired shape. Once the photoablation is complete, a medication is applied to the cornea that is designed to reduce the chance of corneal haze or scarring. The residual medication is then rinsed away with a sterile saline solution and a contact lens is inserted into the eye to serve as a sort of “Band-Aid”. The contact lens will stay in the eye continuously until the epithelial layer grows back over the exposed cornea tissue. The latter typically occurs within 3 to 5 days. During the healing phase the patient frequently instills anti-inflammatory, antibiotic and lubricating eye drops into the eyes. Due to the potential for eye pain, patients are frequently sent home with pain pills and sedative to help with sleep for the first few days postoperatively. The vision will be blurry for several weeks before it begins to clear. Ultimately, the quality of vision will be indistinguishable from Lasik.
At Will Vision and Laser Centers we typically select PRK as an option when a patient’s cornea is not considered to be thick enough to undergo Lasik surgery. However, because we use the iFS Advanced Femtosecond laser we are able to create exquisitely thin Lasik flaps so we can often perform Lasik in patients that have been told that that they need PRK by surgeons who either don’t have access to advanced technology or have inadequate experience with how to safely create thin flaps. In other cases, if a patient is involved in a profession or hobby such as boxing that places the eye at risk for direct trauma, PRK is considered a better option.
If you need PRK and you are in the Portland, Salem or Vancouver, WA area, then we are happy to perform that service using our state-of-the-art wavefront guided technology. In fact, the wavefront guided PRK technology used at Will Vision and Laser Centers is identical to that used by the US military for soldiers in the warfighter program. Dr. Will also has extensive experience with PRK having performed PRK procedures since 1991. However, if you are considering having Lasik surgery as your preferred surgical option but have been told that you only qualify for PRK you might consider giving us a call to see if our thin flap technology can provide you with the option of pursuing Lasik.