What Is Photorefractive Keratectomy and How It Differs from LASIK

A 2018 report from the World Health Organization states that about 1.3 billion people worldwide have imperfect vision. The majority of these people have either a moderate to severe impairment, near vision impairment, or both. Typically, vision problems become much more likely once you reach 50 years old.

If you experience vision issues from a refractive error, you may understand how troublesome it is. You have to deal with paying for contact lenses or eyeglasses every time you go to the eye doctor for a checkup.

Contact lenses can be uncomfortable and expensive. Eyeglasses can be too loose and fall down constantly or they can be too tight and give you headaches. Wouldn’t it be nice to have perfect vision?

Thankfully, LASIK is an option if you qualify for it. This procedure is known for its quick recovery time and ability to majorly improve eyesight.

Another route you may consider is photo refractive keratectomy, or PRK. It takes longer to recover from PRK, but there are some benefits that LASIK doesn’t have. Those who don’t qualify for LASIK might qualify for PRK.

Continue reading to learn the answer to the question, “What is photorefractive keratectomy?” and how it’s different from LASIK.

A Prologue: What is LASIK?

Before getting into the specific procedure of PRK, let’s dive into what LASIK is. Millions of people have heard of LASIK and millions have gotten LASIK. What exactly happens when someone gets LASIK surgery to correct their vision impairment?

LASIK stands for laser-assisted in situ keratomileusis.

LASIK usually takes only 30 minutes (15 minutes for each eye) to complete. Most of this time is spent getting your eyes ready so the laser can do its job safely.

The LASIK Procedure

First, the person is given eye drops that will numb their eyes. Anesthesia isn’t necessary because of how short the procedure is and getting it would come with risks.

A lid spectrum will hold open your eye to prevent you from blinking while the laser is on. You’ll have to stare at a specific spot or target.

A femtosecond laser, which is an extremely precise and fast laser, may be used to make incisions or your doctor may use a microkeratome. A microkeratome is a tiny blade.

Whichever they use, your doctor will cut into your cornea and make a shallow flap. The cornea is the protective layer that covers your eye. Doctors must get under the cornea to access the second cornea layer, known as the stroma.

Next, an excimer laser vaporizes some of the stroma. This laser removes the appropriate amount of stroma in microscopic amounts. The goal is to reshape the cornea.

Refractive errors such as farsightedness and nearsightedness are caused by misshapen corneas. When light enters your eye the cornea bends it so it lands on the retina. This is how people see things clearly.

An oddly-shaped cornea causes blurry vision, but LASIK fixes this by literally changing the shape of the cornea.

If you are farsighted, the doctor will make your cornea more round. People who are nearsighted will be given a flatter cornea. Astigmatisms can be improved by fixing the irregular shape of the cornea.

The top layer of your cornea is then placed back over your eye. This tiny cut will heal during recovery.

Who is a Candidate for LASIK?

Not everyone is qualified to get LASIK. The surgery is a treatment for refractive errors. However, not everyone with a refractive error can get LASIK.

It depends on the cornea, pupil, severity of the error, and other eye problems.

Because LASIK is surgery on the cornea, doctors have to measure the thickness and look at the shape of the cornea. Complications are more likely if you have a thin cornea or an abnormally shaped cornea. However, this doesn’t mean those with astigmatism are ineligible.

People with more severe refractive errors have thinner corneas. You’re less likely to qualify for LASIK if you have a strong prescription.

If your vision impairment is beyond any of these limits, LASIK isn’t a sufficient option and you’ll still need corrective lenses. A doctor may also refuse to do surgery on a patient with moderate vision loss.

Studies have found that patients with pupils larger than average experience worse night vision than those with average-sized pupils. Your doctor will measure your pupil size in dim light.

Anyone with a family history of eye diseases may not qualify. Your doctor will also ask if you have any health problems. Some health issues may make complications more likely.

What is Photorefractive Keratectomy?

Before millions of people had access to LASIK, there was photorefractive keratectomy. It’s a refractive surgery that changes the cornea’s shape just like LASIK. However, there are distinct differences in the procedure.

Recovery takes longer for those who choose PRK – a few weeks or a bit more than a month. The patient often feels discomfort throughout the recovery period. Even after the eyes are fully healed, more time is needed for the person’s vision to reach its peak.

More risks are associated with PRK than LASIK. Both procedures yield similar results in vision improvement. The most common results are 20/20 and 20/40 vision.

The PRK Procedure

As with LASIK, patients will get eye-numbing drops and have their eye held open by a lid spectrum. The main difference in a PRK procedure is how the doctor gets to the stroma.

There is no flap in PRK. The entire top layer of the cornea, called the epithelium, is removed using a femtosecond laser or microkeratome and the stroma is reshaped. A special contact lens bandage is put on each eye after the procedure. PRK only takes 15 minutes.

The recovery period is longer than LASIK because the epithelium has to grow back. This is also the reason why patients feel more discomfort. The epithelium takes a few days to regrow.

Who is a Candidate for PRK?

PRK is good news for people with moderate to severe vision loss. Because there’s no flap created, corneal thickness isn’t an eligibility factor. Mild dry eye isn’t a problem either.

People who are very athletic or at higher risk of eye injury should consider choosing PRK. By completely removing and regrowing the epithelium, there’s no chance for the corneal layer to dislodge and heal the wrong way.

Like LASIK, PRK can’t fix presbyopia. Someone who has health issues, other eye problems such as keratoconus, and a family history of eye problems may not be qualified for PRK.

If your doctor won’t perform LASIK, they may agree to PRK.

The Benefits of PRK

People who get PRK don’t need to worry about damaging or moving the epithelium because there’s no cut made in it. The layer fully regrows and is whole.

PRK gives people with thin corneas, mild dry eye, and those who are active the option to correct their vision.

Many patients experience less severe dry eye after PRK surgery than patients recovering from LASIK.

Comparing LASIK and PRK

Both procedures have the potential to yield 20/20 or 20/40 vision, but the candidacy factors differ because of how the procedures or done. Another major difference is that the epithelium is completely taken off during PRK, which may be a more appealing choice than having a flap on your eye.

Now that you understand LASIK and the answer to “What is photorefractive keratectomy?” you can decide which is the best option.

Don’t hesitate to contact us for a free consultation.