Photorefractive Keratectomy or PRK is a type of refractive laser eye surgery used to correct a patient’s vision to eliminate or reduce their dependence on glasses or contact lenses. PRK is the style of laser eye surgery that preceded LASIK, having been the former most common type of refractive surgery until LASIK came along.
PRK is effective in correcting nearsightedness (myopia), farsightedness (hyperopia) and astigmatism and has very similar rates of success and outcomes as LASIK. PRK remains a common option for laser eye surgery.
How Does PRK Differ From LASIK
PRK and LASIK both permanently reshape the cornea to improve vision by using a laser (an excimer laser to be exact) to remove part of the tissue underneath the corneal epithelium. The epithelium first needs to be removed in order to get access to the tissue and how this is done is what differentiates the two procedures. While LASIK creates and lifts a flap on the outer corneal layer, reshapes the corneal tissue underneath and then replaces the flap, PRK removes the outer layer of the cornea completely. The outer layer will regenerate usually within a few days.
Advantages of PRK
Since PRK completely removes the outer corneal layer, there is a greater area of the cornea to work with. This is ideal for patients with a thin cornea who would otherwise be at risk with LASIK. It is also usually recommended for patients with chronic dry eyes. With PRK, there is also less risk of infection or issues having to do with the flap and the related healing process. This is an advantage for individuals who lead a lifestyle in which they are at risk for eye injuries (athletes, military, law enforcement etc.) which may subject the flap to injury or complications.
So, Why Is LASIK More Popular?
The main advantages that LASIK has over PRK are two-fold and mainly have to do with comfort and recovery time. First of all, PRK patients usually experience slightly more discomfort during the first couple of days of recovery, mainly because it takes time for the outer corneal layer to heal. They will be prescribed eye drops to be taken for several months to prevent infection, increase comfort and assist the healing process. LASIK patients on the other hand, typically experience less discomfort and if they do, it subsides very quickly.
Additionally, vision recovery takes longer with PRK. While LASIK patients can typically see normally within a few hours after the surgery, with vision gradually continuing to improve within the next few months, PRK patients may experience blurred vision for up to three days and it can take up to six months until they achieve full visual clarity. While patients who undergo LASIK can usually drive and resume normal functioning within a day or two, PRK patients shouldn’t plan on returning to normal for at least several days until the outer layer of the cornea has grown back.
Whether PRK or LASIK is a better option for you depends on a number of factors, including the health and structure of your eye. This is a decision that your eye doctor or surgeon will help you make. Rest assured, however, that both procedures have been shown to be incredibly successful in correcting vision, with minimal complications.
What You Need to Know About PRK
Prior to any laser correction surgery, you will meet with a surgeon for a thorough exam to assess your eye health and determine whether you are a candidate and if so, which type of surgery would be best suited to your needs. During this exam, it is essential to tell the doctor any relevant medical history (injuries, hospitalizations, diseases etc.) and existing conditions you have. The surgeon will determine if you are currently eligible for surgery and if not if you will be at a future point, and whether you require any specialized care pre or post surgery.
The surgery itself is an ambulatory procedure. It takes about 15 minutes or less for both eyes and you go home the same day. You will need someone to drive you home from the procedure.
The first step in the procedure is that your eye will be anesthetized using numbing eye drops and then a device will be inserted to prop your eyelids open so you won’t blink. Once the eye is numb, the surgeon will remove the outer epithelial layer of the cornea to expose the underlying tissue. Then the surgeon will use the laser to reshape the corneal tissue. You may feel a small amount of pressure during this step. Lastly, the surgeon will apply medicated eye drops and place a temporary contact lens that is used as a bandage to protect the eye.
Following the surgery, you will be instructed to apply medicated eye drops multiple times each day to reduce the risk of infection and you may also be given prescription pain relievers to alleviate any pain or discomfort.
As with any type of surgery, it is critical to carefully follow your surgeon’s instructions after PRK. Make sure that you take your medication as prescribed, get enough rest, and call your eye doctor immediately if you experience any problems.
It is normal for it to take several days or even weeks for your vision to improve and up to 3-6 months for full recovery to clear and stable visual acuity. Usually, your doctor will require you to refrain from driving for a week and up to three weeks depending on how fast your vision recovers.
Risks and Complications of PRK
While serious complications are rare, like any surgery, there are some risks to PRK, and these happen to be very similar to any laser corrective surgery like LASIK. They include:
- Dry eyes- this condition usually goes away within a couple of months, but there is a chance that it could become chronic.
- Infection or Inflammation- the risk of infection is greatly reduced if you take proper care to follow your doctor’s instructions following the procedure.
- Vision Problems- which can include glare, seeing halos around lights poor night vision and sometimes a general haziness.
- Incomplete Vision Correction - sometimes an additional procedure might be needed to achieve optimal visual acuity.
In general, PRK is considered to be a relatively safe and effective treatment for vision correction. If you wish to live a life without depending on your glasses or contact lenses, speak to your eye doctor about whether PRK is an option for you.