Photorefractive Keratectomy (PRK) is laser eye surgery that is similar to LASIK. The primary difference is that in PRK, no flap is created on the cornea prior to reshaping the eye with an excimer laser.
PRK, which predated LASIK, was once the commonly accepted laser vision correction procedure.
Like LASIK, PRK can correct a wide range of nearsightedness, farsightedness and astigmatism. Many studies still indicate PRK as providing virtually the identical long-term visual outcomes and success rates as LASIK.
Advantages of PRK
The primary advantage of PRK is that there is no risk of flap problems during or after PRK surgery. This is a particularly important consideration for people whose profession is highly active so that their lifestyle introduces greater risk of eye injuries. (military or active law enforcement personnel, sports players, etc.)
A further advantage of PRK is that the laser reshaping of the eye takes place closer to the surface of the cornea compared to LASIK. PRK may therefore be the safer choice for eyes with very thin corneas.
More discomfort is expected during the few days after surgery and vision recovery takes longer after PRK than after LASIK.
PRK patients should not be expected to see well enough for safe driving or even for their normal workday tasks for at least several days after their surgery. Until a new layer of surface cells (epithelial cells) has grown back over the laser-treated portion of the cornea, PRK patients can expect a greater risk of eye infections vs. LASIK patients, during the initial days after surgery.
PRK contains a risk of mild haziness developing in the cornea from the PRK surgery. This corneal haze could last a few months or in some cases, remain permanently. This may not necessarily affect vision. It could take three-to-six months to achieve optimum vision after PRK.
If you are considering PRK, your first step is to choose a surgeon, schedule a pre-operative exam and consultation. During this visit, your PRK surgeon or eye doctor will examine your eyes to determine if you are a proper candidate for laser correction.
Be sure to mention any existent medical conditions you may have and all history of previous eye surgery, illness or injuries. Some conditions may disqualify you altogether as a PRK candidate; others may only postpone your procedure or require specialized post-op care.
PRK is ambulatory: you walk into the surgery, have the procedure, and walk out. The surgery process for both eyes lasts an average of less than 15 minutes. You are awake the entire procedure.
The steps of PRK surgery
- The eye is anesthetized with numbing eye drops.
- A retainer is placed under your eyelids to keep your eye open for the duration of the procedure.
- Once the eye surface is numb, the surgeon removes the thin outer layer of the cornea (the epithelium).
- Next, the excimer laser is positioned directly over your eye.
You will be asked to focus on a small light within the laser-housing for a short period while your surgeon observes through an operating scope.
- The laser is activated and reshapes your cornea. You will hear clicking sounds during the procedure, and you may smell a faint burning odor as well as the feeling of pressure on your eye.
- After the laser completes its mission, medicated eye drops and a bandage contact lens will be applied to your eye.
If you have both eyes done the same day, the surgeon proceeds to the second eye. You may have the option of having PRK surgery for your second eye a week or two later, after the vision in your first eye has recovered.
Your eye surgeon will instruct you to use medicated eye drops several times a day for some time to reduce the risk of infection or inflammation. You may also be administered prescription pain relievers to control discomfort during the initial days just after surgery.
As with any type of eye surgery, it is important to carefully follow your surgeon’s instructions after PRK. Get proper rest, use your medications as directed, and call your eye doctor immediately if you suspect any problem.
PRK recovery takes longer than LASIK surgery recovery. It may require days or even weeks before your eyesight improves significantly. and even longer for full vision stabilization. Typical PRK patients can resume driving a car one to three weeks after surgery, but it could be three-to-six months before vision is totally clear and stable.
You may still need to wear eyeglasses after PRK for specific tasks such as reading or night-driving. In some cases, a second surgery (an enhancement) is required to achieve acceptable visual acuity without glasses or contact lenses.
Risks – Complications
LASIK and PRK have similar risks and potential complications. Some examples are:
- Dry eyes
- Vision problems, poorer night vision, glare, halos and haze
- Incomplete or inaccurate vision correction
- Infection or inflammation following surgery
Your eye doctor or refractive surgeon can give you detailed information about these risks and complications as well as advice about PRK as applied to your specific situation.