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May 16, 2023 | Lasik, SMILE

The Definitive Comparison of SMILE vs Lasik

By Barrett Eubanks, M.D.

The Definitive Comparison of SMILE vs Lasik

If we are comparing names, SMILE eye surgery wins hands down against. SMILE is perhaps the coolest name for a vision correction eye surgery procedure.

But there’s more to SMILE than just the name. It is one of the newest forms of laser eye surgery and gives very successful results.

If you aren’t familiar with SMILE yet, check out Start Here To Learn About SMILE Eye Surgery to learn more about how this procedure works.

Of course, when we look at laser eye surgeries, there is one very dominant treatment - Lasik. So to better understand SMILE, let’s compare and see how it matches up against the most popular way to surgically correct vision and get out of glasses and contact lenses. Let’s see just how well SMILE compares to lasik for the risk, the recovery, the accuracy and how long it lasts.

Let’s Begin - The Procedure

Lasik corrects vision by changing the shape of the cornea. One laser creates a lasik flap while a second laser applies laser energy to the cornea to change the shape. SMILE also changes the shape of the cornea but through a completely different technique. In SMILE, a laser is used to create a thin disc in the middle of the cornea which is then removed through a tunnel - the end result changing the overall shape of the cornea.

Those familiar with lasik know that it is a quick and painless procedure. Overall the procedure takes just about 10 to 15 minutes. If you aren’t familiar, check out How Long Does Lasik Take From Start To Finish

SMILE isn’t much different. It is also a quick painless procedure.

But what about the risk of the procedure?

Again, very similar. Both SMILE and lasik are very low risk procedures.

However, for surgeons, SMILE does have a little bit more of a learning curve than lasik. It is simply more challenging to learn how to remove that thin disc of cornea than to lift up the lasik flap.

Thus, there is a slightly higher risk of complications with SMILE with inexperienced surgeons. This is also especially important if you have a small prescription (which means a thinner and more fragile disc to remove).

As with any surgery, it is important to find good experienced surgeons for the best results. It just becomes more important with SMILE.

But what about long term risk?

Lasik creates a flap within the cornea. While this flap heals up pretty well, it will never be the same as a completely unaltered cornea. This flap can be a source of weakness and can potentially be disrupted and dislodged if hit in the eye. Lasik is traditionally avoided in boxers and MMA fighters because of this reason.

The unique technique of SMILE avoids needing to create a flap within the cornea. This avoids needing to have any worry at all about having any flap issues.

Next Up - The Recovery

The initial recovery isn’t much different from the two as well. For the first day out from both SMILE and LASIK, you can have a scratchy uncomfortable eye. This is from the small “scratch" that both procedures create (the edge of the lasik flap and the SMILE tunnel incision). Technically SMILE may have a little less just due a smaller overall size of the “scratch")

But having a smaller scratch with SMILE is much more important than just that first day.

You see, running through our cornea are tiny little nerves. These nerves are important to help regulate the tears that rest on the surface of our eye and keep them from drying out.

Doing laser eye surgery disrupts these nerves. Especially when using lasers to “cut" near the surface of the eye.

Lasik is known to have dry eye afterwards. And it can take a while for this dry eye to go away. Learn more at Exactly How Long Does Dry Eye Last After Lasik

This is because Lasik creates a large circular “cut" into the cornea to create the lasik flap. This cut involves a very large percentage of the cornea and the nerves that run into the cornea.

In comparison, SMILE only requires a much smaller “cut". Just the small tunnel to remove the disc.

Difference in the size of the cut between lasik and smile
Difference in the size of the cut between lasik and smile; eye image courtesy of 8thstar, CC BY-SA 3.0, via Wikimedia Commons

This is a big difference between the two procedures and significantly affects the recovery. While both procedures can cause a short-term dry eye, SMILE will cause less dry eye and recover faster. This is one of the most significant benefits of SMILE. Frequently, levels of dry eye are back to normal by 3 months out after SMILE.

Having less dry eye afterwards makes for a more pleasant recovery after laser eye surgery with SMILE.

But it can take longer for the vision to become good

Vision sharpens up very quickly after lasik. With SMILE it takes longer.

Removing that disc from the cornea puts the cornea through the “wringer" a little bit more. And the more the cornea is manipulated during surgery, the more short term cloudiness it can develop. Again, surgeon technique and experience have a large influence on this. This makes it take longer for the vision to fully sharpen up after SMILE.

Technically, you may read the letters just fine on the eye chart. But the “quality" of your vision just may not be as good. Things just may not look as good as what you are used to.

In the first few weeks after SMILE, you can have some reduction in the ability to see contrast (which can cause things to look a little faded or like there is a film over your vision). You can also have more halos or trouble focusing.

But you don’t have to wait too long to experience good vision after SMILE. Fortunately much of this resolves by the one month mark after surgery.

Long-Term Outcomes

Ok, now for arguably the most important part - the end result of everything. How well does SMILE and lasik do of correcting vision and does it last?

Things move fast in the eye world. And just as how SMILE was an innovation in the way we use lasers to correct vision, lasik received some innovation on its own.

Lasik has seen the rise of the ability to do more advanced customized treatments. Traditional lasik is only capable of treating the prescription that we have in our glasses and contact lenses. But our eye can contain subtle imperfections that add a small amount of blur and distortions to our vision. These aren't problematic; you can still see well through these imperfections with glasses and contact lenses; but by getting rid of these imperfections, vision can potentially be even better.

Advancements in the ability to map the eye and to map these imperfections have led to the development of custom and topography guided lasik treatments that not only correct vision well but that offer the opportunity to improve vision beyond what is capable with standard contact lenses and glasses. Learn more at Finally Make Sense of All The Different Types Of Lasik.

SMILE isn't customized like these advanced treatments. SMILE simply treats the prescription that you have in your glasses and contact lenses. It's still great, but lasik has the potential to do just a little bit more.

Accuracy & Enhancements

The accuracy of both lasik and SMILE are pretty similar. Both are very accurate with more than 95% having 20/20 vision without glasses or better. But if you do end up off target, treating that residual prescription becomes a little more challenging with SMILE. This is an important consideration the older you are and the larger the treatment you need as the risk of needing an enhancement increases.

For lasik, touch up enhancements are relatively easy and straightforward. The surgeon lifts up the lasik flap, does the treatment and then re-positions the lasik flap.

SMILE isn't as straightforward.

  • Another small disc can be created and removed. But this becomes very difficult or impossible with small prescriptions. It isn’t an officially supported procedure and is rarely done.
  • Lasik can be performed just above the SMILE treatment. But this requires a thinner lasik flap with the potential for more flap issues than standard lasik.
  • The SMILE treatment can be converted into a flap. But this isn't ideal with high prescriptions and also the software that allows this isn’t available for use in the U.S.
  • So most patients end up getting PRK as a touch up after SMILE. PRK has a much longer recovery time than lasik or SMILE and will have more dry eye than SMILE.

Either way, needing to have an enhancement after SMILE negates some of the main benefits of the procedure in the first place, whether avoiding the need for a flap or having less dry eye afterwards.

Does the treatment last?

At least, the good news is that SMILE treatments are very stable over the long-term. The treatment doesn't wear off. The long-term results of SMILE may potentially be even better than lasik; however, there isn't any good recent comparison to really say for sure.

So Which One Is Best?

Here are the top reasons you should choose SMILE over lasik

  • You have a moderate amount of dry eye and / or desire to have a quicker recovery of dry eye after the procedure
  • You want to avoid potential issues with having a lasik flap

But conversely, here are the main reasons to pick lasik over SMILE

  • You have a farsighted prescription. SMILE can't treat those prescriptions.
  • You have a large amount of astigmatism. SMILE can only treat up to 3.00 of astigmatism.
  • You desire to have the treatment fully customized to the shape and topography of your individual cornea for better potential vision
  • You desire to have a quicker recovery of vision following the procedure

Really both procedures work great and a lot comes down to personal preferences and goals.

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