PRK
PREPARING FOR PRK
Although most PRK patients are already doing quite well at their one-month examination, it may take several months before the entire extent of your vision correction is apparent. Often, patients who are severely nearsighted or farsighted must wait longest for their full results. Your final vision outcome may not be known for certain for a few months, or more, after your procedure. The surface of the eye needs to heal fully before the doctor can actually determine the final results.
PRK Statistics
Published studies demonstrate no difference in the final results between PRK and LASIK at one year after the procedure. As with LASIK, your personal statistics depend on your degree of correction. The smaller your correction, the better the chance of perfect vision. However, even patients with severe nearsightedness report positive results with PRK. Chapter 10 will give you an idea of your chances of 20/20 vision with PRK.
When Retreatment Is Needed
In approximately 5 to 10 percent of PRK cases, a retreatment, or enhancement, may be necessary to achieve the optimal level of vision correction you and your surgeon hoped for. During a PRK retreatment, surface cells are removed, and you will experience another one to two days of mild to moderate discomfort. Again, though, you will be prescribed the medication to ease any discomfort. A minimum wait of six months after the original PRK is required for the eyes to become sufficiently stable for laser enhancement.
Potential Complications
In general, the complications of PRK and LASIK are the same. Refer to chapter 8 for a discussion of the complications of LASIK. The information in that chapter applies to PRK, too, with the following differences.
Absence of Flap Complications
One advantage of PRK over LASIK is that there is no risk of flap complications because no corneal flap is created.
Corneal Haze
Corneal haze is clouding of the cornea during the healing process. This clouding may cause blurry or hazy vision. Significant corneal haze following PRK is extremely rare with today's equipment and medications. As a general rule, the worse your eyesight was going into the procedure, the more you are at risk for developing corneal haze. Haze eventually disappears by itself, but this can take months or years. If it develops, corneal haze is usually retreated with the laser to physically remove it, although this is necessary in fewer than 1 percent of patients. Corneal haze does not occur with LASIK.
Comparing PRK with LASIK Surgery
Range of Correction
PRK and LASIK cover the same range of correction-low to moderate farsightedness and low to high nearsightedness with or without astigmatism.
Depth of Penetration
Because no corneal flap is created, the depth of penetration of PRK into the cornea is less than LASIK. PRK alters only the surface of the cornea. LASIK, on the other hand, penetrates into deeper layers of the cornea.
Recovery of Vision
The recovery from PRK is slower than LASIK. After LASIK, your vision is usually 20/20 or close to it by the next morning. With PRK, vision does not reach this level for 3 to 5 days. Because most of us need to see well in order to perform our jobs, this timeline can be used for going back to work. So, if you have PRK completed in both eyes at the same time, you'll most likely need to take a couple of additional days off from work.
Discomfort
Because your eyes are numb during surgery, you will feel no pain during either LASIK or PRK. Mild to moderate discomfort is typical with PRK during the first twenty-four to forty-eight hours after surgery. The discomfort is caused by the absence of the epithelium, and disappears as the new epithelium grows over the area of laser treatment. In LASIK, the epithelium is not removed, so post-operative pain is usually minimal and lasts only about two to four hours.
Medications
Postoperative medications also vary between the procedures. PRK patients may use medicated eyedrops for anywhere from 1 week to three months after surgery. LASIK patients, on the other hand, are typically finished with their medications within a week after surgery.
Final Vision
