Bryan Wolynski, OD, is a board-certified community optometrist who has been in the eye care field for over 30 years. He works in private practice in New York City.

You may be considering undergoing refractive laser surgery to correct your nearsightedness (myopia), farsightedness (hyperopia), or unevenness in the shape of your cornea or lens (astigmatism).

With the aid of an excimer laser, a surgeon can reshape the cornea , the clear dome of the eye, so that light properly hits the retina (the nerve-rich layer that relays images to the brain). The idea is to be able to free you either entirely or somewhat from glasses or contacts.

Both photorefractive keratectomy (PRK) and laser-assisted in situ keratomileusis (LASIK) use the excimer laser to correct vision. You may wonder which of these would be best suited to your needs.

This article will explain how PRK and LASIK work, what to expect during each treatment, which would more likely suit you, and what to know about potential side effects.

PRK was the first refractive excimer laser procedure to be performed and remains a solid option.

PRK aims to reshape the cornea's surface using an excimer laser. The laser ablates (removes) the cells on top of the cornea to help sharpen vision.

The reshaped cornea can then help incoming light land right on the retina instead of in front of it or behind it, as occurs with nearsightedness or farsightedness. The laser can also smooth corneal irregularities that may occur with astigmatism and otherwise cause distortion.

During this procedure, the outermost layer, known as the corneal epithelium, is first removed. Then the excimer laser is used to reshape the cornea. The corneal epithelium grows back over the reshaped cornea in about three to four days.

When you undergo the PRK procedure, which takes about 15 minutes, your ophthalmologist (medical doctor trained to diagnose and treat eye conditions, as well as perform surgery on the eyes) will:

While the PRK procedure may go smoothly, there is always the risk of complications. These include:

These complications can be treated. In rare instances, complications can lead to vision that is not as good as before the surgery. Very rarely, blindness may occur.

As a rule of thumb, PRK has fewer steps and tends to be slightly less expensive than LASIK. The cost of this procedure may vary depending on your location and the specific center you choose.

Fees range from around $1,500 to $3,000 per eye. Since this is considered an elective procedure, it is unlikely to be covered by insurance.

You can find PRK services at private outpatient eye institutes and university centers.

LASIK, which applies excimer laser energy to a slightly different area than PRK, is also a very viable option for helping to reduce the need for wearing glasses and contacts.

With LASIK, the excimer laser energy is not applied on the cornea's surface as in PRK. Instead, a flap of corneal tissue is created and flipped temporarily back.

The excimer laser energy is then aimed at the corneal tissue beneath the flap. The laser reshapes it to compensate for nearsightedness or farsightedness and to correct irregularities associated with astigmatism. Once this is done, the flap is then returned to its usual position.

The reshaped cornea can then focus the light on the retina.

During the LASIK procedure, a corneal flap will be created and lifted out of the way. The excimer laser will be aimed at the tissue beneath it to reshape the cornea.

As part of the LASIK procedure, you can expect the following:

Another possibility is undergoing custom LASIK. This approach involves creating a three-dimensional map of your eye and any unique aberrations it may have.

Then the eye surgeon will use what's known as wavefront-guided laser technology to customize the LASIK and treat any unique aberrations (imperfections) that may be interfering with your best vision.

After undergoing LASIK, there is the possibility of the following common complications:

With LASIK, while most complications can be quickly resolved, there's also the possibility of infection. You might have worse vision than before surgery, even with glasses or contacts. There's also the possibility of vision loss.

Traditional LASIK prices can vary from around $1,000 to $4,000 per eye. If you have custom LASIK, costs will be at the upper part of this range and possibly even beyond.

You can get LASIK at outpatient surgery facilities, as well as at university centers.

Should you undergo PRK or opt for LASIK? That's an individual decision to be made with the assistance of an ophthalmologist. Factors to consider include:

While you may initially opt to undergo a LASIK procedure, if you need to have your prescription changed later, it's not uncommon to undergo what's known as an enhancement.

At that point, your ophthalmologist may recommend PRK to avoid lifting the LASIK flap, which brings with it some risks. Lifting the flap may cause it to become damaged in the process, especially if it has been several years since the initial LASIK was performed.

If you find yourself contending with side effects after laser refractive surgery, these options may help:

PRK and LASIK are two forms of excimer laser refractive surgery that can address common vision problems such as nearsightedness, farsightedness, and astigmatism. Either can potentially reduce your need for glasses and contact lenses. Both use an excimer laser to reshape the cornea.

The key difference between them is that PRK is done on the eye's surface, while LASIK is performed beneath a corneal flap. Deciding which is right for you means weighing your unique eye needs and your lifestyle.

With an elective procedure such as PRK or LASIK, provided nothing about your eye rules out one or the other, the choice of which of these to undergo will be yours. There's not necessarily a right answer—in many cases, it will simply come down to preference.

The good news is that either of these procedures can ultimately sharpen your vision and make you less dependent on glasses or contact lenses. You should still continue to see your eye doctor regularly for comprehensive eye exams afterward to ensure you are not developing other eye conditions.

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American Academy of Ophthalmology. What is photorefractive keratectomy (PRK)?

Nvision. How expensive is PRK? Costs to expect in 2022.

American Academy of Ophthalmology. LASIK - laser eye surgery.

Nvision. How much LASIK surgery actually costs in 2022.

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American Academy of Ophthalmology. Do you have any advice for clearing haze after PRK surgery?

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