Photorefractive keratectomy (PRK) and laser-assisted in situ keratomileusis (LASIK) are both laser surgery techniques used to help improve eyesight. PRK has been around longer, but both are still widely used today.
PRK and LASIK are both used to modify the cornea of your eye. The cornea is made up of five thin, transparent layers of tissue over the front of your eye that bend (or refract) and focus light to help you see.
PRK and LASIK each use different methods to help correct your vision by reshaping cornea tissue.
With PRK, your eye surgeon takes away the top layer of the cornea, known as the epithelium. Your surgeon then uses lasers to reshape the other layers of the cornea and fix any irregular curvature in your eye.
With LASIK, your eye surgeon uses lasers or a tiny blade to create a small flap in your cornea. This flap is raised up, and your surgeon then uses lasers to reshape the cornea. The flap is lowered back down after the surgery is complete, and the cornea repairs itself over the next few months.
Either technique can be used to help resolve eye issues related to:
- nearsightedness (myopia): inability to see distant objects clearly
- farsightedness (hyperopia): inability to see close objects clearly
- astigmatism: an irregular eye shape that causes blurry vision
Read on to learn more about the similarities and differences of these procedures, and which one may be right for you.
The two procedures are similar in that they both reshape irregular cornea tissue using lasers or tiny blades.
But they differ in some crucial ways:
- In PRK, part of the top layer of cornea tissue is removed.
- In LASIK, a flap is created to allow an opening to the tissues below, and the flap is closed again once the procedure’s done.
What happens during PRK?
- You’re given numbing drops so that you don’t feel any pain during the surgery. You may also receive medication to help you relax.
- The top layer of cornea tissue, the epithelium, is fully removed. This takes about 30 seconds.
- An extremely precise surgical tool, called an excimer laser, is used to fix any irregularities in the deeper corneal tissue layers. This also takes about 30-60 seconds.
- A special bandage that’s similar to a contact lens is put on top of the cornea to help the tissues beneath heal.
What happens during LASIK?
- You’re given drops to numb your eye tissues.
- A small flap is cut into the epithelium using a tool called a femtosecond laser. This allows your surgeon to move this layer to the side while the other layers are reshaped with lasers. Because it remains attached, the epithelium can be put back in its place after the surgery’s done, rather than being fully removed as it is in PRK.
- An excimer laser is used to reshape corneal tissues and fix any issues with eye curvature.
- The flap in the epithelium is put back in its place over the rest of the cornea tissue to let it heal with the rest of the tissues.
During each surgery, you’ll feel a little bit of pressure or discomfort. You may also notice some changes in your vision as your surgeon modifies eye tissue. But you won’t feel any pain.
Full recovery with PRK will usually take about a month or so. Recovery from LASIK is faster, and should only take a few days to see better, although complete healing takes several months.
Following PRK, you’ll have a small, contact-like bandage over your eye that may cause some irritation and sensitivity to light for a few days as your epithelium heals. Your vision will be a little blurry until the bandage is removed after about a week.
Your doctor will prescribe lubricating or medicated eye drops to help keep your eye moist as it heals. You may also get some medications to help relieve pain and discomfort.
Your vision will be noticeably better right after surgery, but it may worsen a bit until your eye fully heals. Your doctor may instruct you not to drive until your vision has normalized.
The complete healing process lasts about a month. Your vision will slowly get better each day, and you’ll see your doctor regularly for checkups until your eye is fully healed.
You’ll probably see much more clearly right after LASIK than you could before, even without glasses or contacts. You may even have close to perfect vision the day after your surgery.
You won’t experience much pain or discomfort as your eye heals. In some cases, you may feel some burning in your eyes for a few hours after the surgery, but it shouldn’t last long.
Your doctor will give you some lubricating or medicated eye drops to take care of any irritation, which may last for a few days.
You should be fully recovered within a few days following your procedure.
Both techniques are equally effective in permanently correcting your vision. The main difference is the recovery time.
LASIK takes a few days or less to see clearly while PRK takes about a month. The final results won’t differ between the two if the procedure is done properly by a licensed, experienced surgeon.
Overall, PRK is considered to be safer and more effective in the long term because it doesn’t leave a flap in your cornea. The flap left behind by LASIK can be subject to greater damage or complications if your eye is injured.
Both procedures have some risks.
LASIK may be considered a little riskier because of the additional step needed to create a flap in the cornea.
Possible risks of these procedures include:
- Eye dryness. LASIK, especially, can make you produce fewer tears for about six months after surgery. This dryness can sometimes be permanent.
- Visual changes or disturbances, including glares from bright lights or reflections off objects, halos around lights, or seeing double. You might also not be able to see well at night. This often goes away after a few weeks, but can become permanent. Talk to your doctor if these symptoms don’t fade after about a month.
- Undercorrection. Your vision may not seem that much clearer if your surgeon didn’t remove enough corneal tissue, especially if the surgery was done to correct nearsightedness. If you’re not satisfied with your results, your doctor may recommend a follow-up surgery to get you the results you want.
- Visual distortion. Your surgeon may remove more corneal tissue than necessary, which can cause distortions to your vision known as ectasia. This can make your cornea too weak and make your eye bulge from pressure inside the eye. Ectasia needs to be resolved to prevent possible vision loss.
- Astigmatism. Your eye curvature can change if corneal tissue isn’t removed evenly. If this happens, you may need a follow-up surgery, or need to wear glasses or contacts for full correction of your vision.
- LASIK flap complications. Issues with the corneal flap made during LASIK can lead to infections or producing too many tears. Your epithelium can also heal irregularly beneath the flap, leading to visual distortion or discomfort.
- Permanent vision loss. As with any eye surgery, there’s a tiny risk of damage or complications that lead to partial or total loss of your vision. Your vision may seem a little more cloudy or blurry than before, even if you can see better.
Here are the basic eligibility requirements for each of these surgeries:
- you’re over 18
- your vision hasn’t changed significantly in the last year
- your vision can be improved to at least 20/40
- if you’re nearsighted, your prescription is between -1.00 and -12.00 diopters, a measurement of lens strength
- you’re not pregnant or breastfeeding when you get the surgery
- your average pupil size is about 6 millimeters (mm) when the room is dark
Not everyone is eligible for both surgeries.
Here are some situations that may make you ineligible for one or the other:
- You have chronic allergies that can affect your eyelids and eye healing.
- You have a major condition that affects the eye, such as glaucoma or diabetes.
- You have an autoimmune condition that can affect your healing, such as rheumatoid arthritis or lupus.
- You have thin corneas that may not be sturdy enough to handle either procedure. This usually makes you ineligible for LASIK.
- You have large pupils that increase your risk of visual disturbances. This also can make you ineligible for LASIK.
- You’ve already had an eye surgery in the past (LASIK or PRK) and another may increase your risk of complications.
In general, both surgeries cost about $2,500-$5,000.
PRK may be more expensive than LASIK because of the need for more post-op check-ins to remove the bandage and monitor your eye’s healing over the course of a month.
LASIK and PRK aren’t usually covered by health insurance plans because they’re considered elective.
If you have a health savings account (HSA) or flexible spending account (FSA), you may be able to use one of these options to help cover the cost. These plans are sometimes offered through employer-sponsored health benefits.
Here are the main pros and cons of these two procedures.
|LASIK||• Quick recovery (< 4 days for vision)|
• No stitches or bandages needed
• Fewer follow-up appointments or medications needed
• High rate of success
|• Risk of complications from flap |
• Not recommended for people with high risk of eye injury
• Higher chance of dry eye
• Greater risk of poor night vision
|PRK||• Long history of success|
• No flap created during surgery
• Small chance of long-term complications
• High rate of success
|• Long recovery (~30 days) that can be disruptive to your life|
• Requires bandages that need to be removed
• Discomfort lasts for several weeks
Here are some tips on how to find the best provider to perform either procedure, and some questions you should ask any potential provider:
- Look at several providers near you. See how their experience, costs, patient ratings, technology use, and success rates stack up to each other. Some surgeons are more experienced or better trained in one procedure or the other.
- Don’t settle for the cheapest option. Saving some money may not make up for the increased risk and expense of lifelong complications.
- Don’t fall for advertising claims. Don’t believe any surgeons who promise specific results or guarantees, as any surgical procedure is never 100 percent guaranteed to give you the results you want. And there’s always a small chance of complications beyond the surgeon’s control in any surgery.
- Read any handbooks or waivers. Carefully examine any pre-op instructions or paperwork given to you before surgery.
- Make sure you and your doctor have realistic expectations. You may not have 20/20 vision after surgery, but you should clarify the expected improvement to your vision with your surgeon before any work is done.
LASIK and PRK are both good options for visual corrective surgery.
Talk to your doctor or eye specialist about which option may be better for you based on the specifics of your eye health as well as your overall health.