PRK or photorefractive keratectomy is one of the safest and most time-tested laser vision correction procedures available. Before LASIK, PRK was the most common refractive surgery procedure. Like LASIK, it reshapes the cornea to improve vision. PRK is now used mainly for patients with large pupils or thin corneas.
Studies have shown that 90-95% of patients with a correction of up to -6.00 diopters achieve the vision of 20/40 after PRK, and up to 70% achieve 20/20. Patients needing less correction generally achieve better results. The risks of PRK include infection, haze, slow healing, scarring, over- or under-correction of the visual condition, and development of astigmatism.
What Is Photorefractive Keratectomy?
Photorefractive keratectomy, PRK for short, is a type of refractive surgery to correct nearsightedness, farsightedness, and astigmatism. Although LASIK surgery has become more popular, PRK was actually the first type of laser surgery performed for vision correction. While both LASIK and PRK reshape the cornea to correct refractive errors, the difference is that in PRK the epithelium, the thin membrane protecting the cornea, is removed to gain access to the cornea. In LASIK a flap is created to gain access. The necessary growing of a new epithelium can make PRK recovery somewhat more involved than LASIK
Am I A Candidate For PRK?
Like LASIK, PRK reshapes the cornea and corrects refractive errors that lower visual quality. So, if you have refractive errors and would like to remove the need for wearing corrective eyewear, PRK or LASIK are both great procedures. But because PRK doesn’t create a flap in the corneal stroma, it could be a better procedure for patients with thin or irregular corneas, or for those concerned about complications with the flap created in LASIK. PRK also is a superior option for patients with large pupils.
What concerns can PRK help fix?
PRK can correct nearsightedness, farsightedness, and astigmatism. In this procedure, Dr. Maehara uses our excimer laser to reshape the cornea, correcting the refractive errors.
PRK can be a better option than LASIK when a patient has thin or irregular shaped corneas. That’s because PRK doesn’t create a flap in the corneal stroma. This can also make it a better choice for participants in contact sports or certain occupations that involve being bumped or hit in the eye. That’s because the flap created in LASIK can move out of place, and with PRK there isn’t a flap.
What Is Involved In The PRK Surgery?
Dr. Jeffrey Maehara performs our PRK procedures. The first step is to place anesthetic eye drops in the patient’s eyes. This ensures the brief procedure is completely painless. Next, we place a device to keep your eyelid retracted.
PRK has two basic steps:
- Removal of the outer corneal layer, the epithelium. This will grow back.
- Laser reshaping of the cornea’s middle layer called the strong.
The epithelium is removed in one of three ways:
- It can be soaked with a weak alcohol solution to soften the tissue, making it easy to remove.
- The outer layers can be removed with a sponge or brush.
- The outer layers can be removed with the excimer laser that will reshape the cornea.
Once the epithelium is removed, the excimer laser reshapes the cornea. This reshaping corrects the refractive errors that either focus too far (farsightedness) or near (nearsightedness), or when the cornea is more oblong than round (astigmatism).
The surgery takes just 15 minutes.
“I was suffering from vision distortion due a surgery that I had with another doctor. I went to 3 other surgeons for get help and thousands of dollars. I even saw a surgeon in Texas. None of them could help me. I thought I was going to have to live with the vision distortion forever. On my 1st visit to see Dr. Maehara he knew exactly what the problem was. I had to do another surgery, but ever since then my vision is no longer distorted and I can see! Now I send all my family and friends to him. There is no one else that I will ever trust with my vision again!”
What results can PRK surgery achieve?
Long-term results from PRK are the same as with LASIK, but as mentioned above, some patients are better suited for PRK. PRK allows patients with wide ranges of refractive errors to see, often for the first time in their lives, without the use of corrective eyeglasses or contact lenses. Patients are thrilled to be able to wake up and actually read the alarm clock numbers, rather than having to first reach for their glasses to do so. Playing sports is more fun without having to deal with fogging glasses or sweat getting on lenses. Some patients who have opted not to wear glasses when playing sports due to the hassle often find out they now can perform better after their PRK procedure with Dr. Maehara. Just seeing things clearly all the time without help thrills our PRK and LASIK patients.
What is the success rate for PRK?
Studies have shown the success rate with PRK to be roughly 99 percent when patients are asked if they are satisfied with the results of their laser surgery. Overall, 95 percent of patients achieve 20/40 vision or better. Seventy percent achieve perfect 20/20 vision.
Does PRK Surgery Hurt?
Like LASIK surgery at Maehara, PRK is also painless. We place anesthetic eye drops in both eyes prior to the PRK procedure. This means you’ll feel nothing.
What to Expect During Recovery
Because the epithelium is removed with PRK, recovery is somewhat more involved than with LASIK. Still, it is not an overly difficult recovery.
Immediately after your surgery, you’ll rest for a brief time and then someone will drive you home. We prescribe topical antibiotics as well as anti-inflammatory and pain medication. These will work to keep you comfortable, minimize swelling, and speed the healing process.
Since the epithelium has to grow back, PRK recovery takes longer than LASIK. Dependent upon your rate of growth, your recovery can vary from a few days to a couple of weeks before your eyesight really improves. In most cases, PRK patients can drive a car in one to three weeks, but it can take up to six months for your vision to fully clear and for your final results to stabilize.
What will my vision be like after PRK surgery?
After this laser surgery, you’ll need someone to drive you home. You may have some mild eye pain for the first 24-36 hours, but this can be handled with eye drops. You will have a “foreign body” sensation in your eyes. It’s wise to nap for a few hours, if possible, to get past the worst of your discomfort. For the first week or two, you may have some blurred vision, and your eyes will be more sensitive to light. From there, your vision will continue to improve toward its final excellent state.
PRK vs. Lasik Eye Surgery
In PRK the epithelium is removed. This will grow back, but this aspect of PRK does make for a somewhat longer recovery than with LASIK. In LASIK, Dr. Maehara doesn’t remove the epithelium. Instead, a flap is created in the cornea stroma. Making this flap provides the same access to the cornea that removing the epithelium does. With PRK, the epithelium has to grow back after surgery. In LASIK, the flap has to heal, which happens more quickly. But there can sometimes be complications with the flap.
What Are Advantages Of PRK Surgery?
An advantage to PRK over LASIK is the elimination of the flap. This removes the chance for complications with the flap. PRK is suitable for patients with a thin cornea, whereas LASIK may not be. At Maehara, we perform bladeless LASIK, which removes any irregularities with the flap. PRK can be a better procedure for patients with large pupils, as well.
What Are The Disadvantages Of PRK Surgery?
As the difference between these refractive surgeries is the epithelium (removal or not), that is the main disadvantage to PRK. PRK can have a slower visual recovery than with LASIK. PRK can take weeks for the full recovery of functional vision, whereas LASIK takes only days to return to functional vision. PRK usually also involves more discomfort during the first several days of recovery, with burning or watery eyes. Vision can also fluctuate as the epithelial tissue regrows. Final results tend to take longer with PRK than LASIK.
Is PRK safe? What are the risks and side effects?
Both PRK and LASIK are incredibly safe and effective surgeries. They have been performed tens of millions of times around the world. Complications are quite rare, and they can usually be addressed with a second, much more limited surgery.
These are the risks of PRK:
- Under or overcorrection
- Corneal haze
- Corneal scarring
- Decreased night vision
- Glare and halos
- Overall decreased vision
Is PRK Surgery Covered By Insurance?
PRK and LASIK are both deemed elective procedures to improve a patient’s quality of vision. They are not deemed necessary or required. Because of that, health insurance rarely covers these surgeries.